Two-level led security light with motion sensor

ABSTRACT

A technology for configuring a lifestyle LED light with a tunable light color temperature is disclosed. The technology of tuning the light color temperature is made possible by blending two LED loads emitting light with different color temperatures thru a light diffuser with an arrangement that a first electric power delivered to a first LED load emitting light with a low color temperature and a second electric power delivered to a second LED load emitting light with a high color temperature are reversely and complementarily adjusted for tuning a diffused light color temperature such that a total light intensity generated by the LED light is kept essentially unchanged.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of prior application Ser. No. 17/202,879, filed on Mar. 16, 2021. Application Ser. No. 17/202,879 is a continuation application of prior application Ser. No. 16/159,852, filed on Oct. 15, 2018, which issued as U.S. Pat. No. 10,985,596 on Apr. 20, 2021. Application Ser. No. 16/159,852 is a continuation application of prior application Ser. No. 15/393,768, filed on Dec. 29, 2016, which issued as U.S. Pat. No. 10,136,495 on Nov. 20, 2018. Application Ser. No. 15/393,768 is a continuation application of prior application Ser. No. 15/213,595, filed on Jul. 19, 2016, which issued as U.S. Pat. No. 9,622,328 on Apr. 11, 2017. Application Ser. No. 15/213,595 is a continuation application of prior application Ser. No. 14/478,150, filed on Sep. 5, 2014, which issued as U.S. Pat. No. 9,445,474 on Sep. 13, 2016. Application Ser. No. 14/478,150 is a continuation application of prior application Ser. No. 13/222,090, filed on Aug. 31, 2011, which issued as U.S. Pat. No. 8,866,392 on Oct. 21, 2014.

INCORPORATION BY REFERENCE/MPEP 2163.07(b)

-   -   The following prior arts with associated disclosures are herein         requested to be incorporated into the current application:     -   1. U.S. Pat. No. 9,345,112 B2 titled “MICROCONTROLLER-BASED         MULTIFUNCTIONAL ELECTRONIC SWITCH AND LIGHTING APPARATUS HAVING         THE SAME” filed on Dec. 22, 2014 and granted on May 17, 2016.         The '112 Patent is a continuation in part of the original         application of U.S. Pat. No. 8,947,000 which is the first         founding patent for a large family collection of member patents         involving using the technology of the microcontroller based         electronic switch to control a light intensity of a         light-emitting unit. The '112 Patent is in turn the second         founding patent for a subfamily of member patents involving         using a technology of two LED loads emitting light with         different color temperature to work with the technology of the         microcontroller-based electronic switches to control a color         temperature tuning and switching scheme of an LED load.         -   The applicant herein requests to incorporate the contents of             the '112 Patent including all disclosures, embodiments and             drawings to the specification of the current application             according to MPEP 2163.07(b).     -   2. U.S. Pat. No. 10,136,503 B2 titled “MICROCONTROLLER-BASED         MULTIFUNCTIONAL ELECTRONIC SWITCH AND LIGHTING APPARATUS HAVING         THE SAME” filed on Sep. 13, 2017 and granted on Nov. 20, 2018.         The '503 Patent is a member patent in the family collection of         member patents under the first founding patent '000 and is also         a member patent in the subfamily collection of member patents         under the second founding Patent '112.         -   The '503 Patent teaches a system and a method of using two             microcontroller based electronic switches respectively             connected to two LED loads emitting light with different             color temperatures to control and allocate different             electric powers respectively delivered to the two LED loads             for performing multiple working modes including on/off             control mode, dimming mode, color temperature tuning mode,             color temperature switching mode, color temperature dim to             warm mode, commanding mode for controlling a lighting family             comprising a plurality of member lamps remotely located or             delay shut off mode.         -   The applicant herein requests to incorporate the contents of             the '503 Patent including all disclosures, embodiments and             drawings to the specification of the current application             according to MPEP 2163.07(b).     -   3. U.S. Pat. No. 10,470,276 B2 titled “METHOD OF TUNING LIGHT         COLOR TEMPERATURE FOR LED LIGHTING DEVICE AND APPLICATION         THEREOF” was filed on Oct. 17, 2018 and granted on Nov. 5, 2019.         The '276 Patent teaches a method and application of performing a         light color temperature tuning control for an LED lamp includes         using a first LED load emitting light with a low color         temperature and a second LED load emitting light with a second         color temperature thru a light diffuser, using a power         allocation circuitry working with a power allocation algorithm         to control different electric power respectively delivered to         the first LED load while keeping the total electric power         unchanged to generate different diffused light color         temperatures. Applicant herein requests to incorporate the         contents of the '276 Patent including all disclosures,         embodiments and drawings by reference to the specification of         the current application according to MPEP 2163.07(b).     -   4. U.S. Pat. No. 11,063,585 titled “METHOD OF TUNING LIGHT COLOR         TEMPERATURE FOR LED LIGHTING DEVICE AND APPLICATION THEREOF” was         a continuation of application of the '276 Patent, filed on Aug.         7, 2019 and granted on Jul. 13, 2021. The '585 Patent discloses         a theory and a technical foundation for building a technical         frame of a color temperature tuning technology for an LED lamp         composing a power allocation algorithm, a power allocation         circuitry and at least one external control device for         activating a color temperature tuning and switching scheme.         -   The applicant herein requests to incorporate the contents of             the '585 Patent including all disclosures, all embodiments             and all drawings to the specification of the current             application according to MPEP 2163.07(b).     -   5. U.S. Pat. No. 8,866,392 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was filed on Aug. 31, 2011 and granted         on Oct. 21, 2014. The '392 Patent discloses technologies for         operating a two level LED security light; at night the LED         security light is automatically turned on for a low level         illumination, when a motion intrusion signal is detected by the         motion sensor, the LED security light is switched from the low         level illumination with a low color temperature to a high level         illumination with a high color temperature to maximize an effect         of security alert for a short duration time, at dawn the LED         security light is automatically turned off.         -   The '392 Patent is the founding application for a large             family collection of member patents involving automatic             illumination control technologies including light intensity             tuning and light color temperature tuning. The applicant             herein requests to incorporate the contents of the '392             Patent including all disclosures, embodiments and drawings             to the specification of the current application according to             MPEP 2163.07(b).     -   6. U.S. Pat. No. 10,516,292 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was a member patent under the founding         patent '392, filed on Jan. 10, 2019 and granted on Dec. 24,         2019.         -   The '292 Patent is a member patent in the family collection             of patents under the founding patent '392.         -   The '292 Patent discloses a lifestyle LED security light             including a light-emitting unit configured with two sets of             LED loads respectively emitting different color temperature             light, at dusk the light-emitting unit is automatically             turned on for a first level illumination with a low color             temperature featuring an aesthetic night view with the             motion sensor being deactivated for a first time duration,             and then the light-emitting unit is changed to a second             level illumination with motion sensor being activated, when             the motion sensor detects a motion intrusion signal, the             light-emitting unit is instantly switched to perform a third             level illumination with a high light intensity and a high             color temperature. The color temperatures of the first level             illumination and the third level illumination are             respectively adjustable by simultaneously and reversely             adjusting the electric powers allocated to the two sets of             LED loads.         -   The applicant herein requests to incorporate the contents of             the'292 Patent to the specification of the current             application according to MPEP 2163.07(b).     -   7. U.S. Pat. No. 10,770,916 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was filed on Oct. 30, 2019 and granted         on Sep. 8, 2020. The '916 Patent is a member patent in the         family collection of patents under the founding patent '392. The         '916 Patent teaches a method of configuring an LED light with a         tunable diffused light color temperature. The method comprises         using a light-emitting unit configured with a first LED load         emitting light with a low color temperature and a second LED         load emitting light with a high color temperature electrically         connected in parallel, using a light diffuser to cover the first         LED load and the second LED load create a diffused light with a         diffused light color temperature, using two semiconductor         switching devices working in conjunction with a controller to         respectively control a first electric power delivered to the         first LED load and a second electric power delivered to the         second LED load to operate a color temperature tuning and         switching scheme and using a first external control device to         output at least one first external control signal to activate a         selection of a diffused light color temperature.         -   The applicant herein requests to incorporate the contents of             the '916 Patent including all disclosures, all embodiments             and all drawings to the specification of the current             application according to MPED 2163.07((b).     -   8. U.S. Pat. No. 10,763,691 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was filed on Mar. 19, 2020 and granted         on Sep. 1, 2020. The '691 Patent is a member patent in the         family collection of patents under the original founding patent         '392. The '691 Patent discloses a technology of tuning the light         color temperature of a lifestyle LED light by blending the two         LED loads emitting light with different color temperatures thru         a light diffuser with an arrangement that a first electric power         delivered to a first LED load emitting light with a low color         temperature and a second electric power delivered to a second         LED load emitting light with a high color temperature are         reversely and complementarily adjusted for tuning a diffused         light color temperature such that a total light intensity         generated by the LED light is kept essentially unchanged.         -   The applicant herein requests to incorporate the contents of             the '691 Patent including all disclosures, embodiments and             drawings to the specification of the current application             according to MPEP 2163.07(b).     -   9. U.S. Pat. No. 10,187,947 B2 titled “LIFE-STYLE LED SECURITY         LIGHT” was issued on Jan. 22, 2019. The applicant herein         requests to incorporate the contents of the '947 Patent         including all disclosures, embodiments and drawings to the         specification of the current application according to MPEP         2163.07(b).     -   10. U.S. Pat. No. 10,491,032 B2 titled “LIFESTYLE SECURITY         LIGHT” was issued on Nov. 26, 2019. The applicant herein         requests to incorporate the contents of the '032 Patent         including all disclosures, embodiments and drawings to the         specification of the current application according to MPEP         2163.07(b).     -   11. U.S. Pat. No. 10,225,902 B2 titled “TWO-LEVEL SECURITY LIGHT         WITH MOTION SENSOR” was issued on Mar. 5, 2019. The applicant         herein requests to incorporate the contents of the '902 Patent         including all disclosures, embodiments and drawings to the         specification of the current application according to MPEP         2163.07(b).     -   12. U.S. Pat. No. 10,326,301 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was issued on Jun. 18, 2019. The         applicant herein requests to incorporate the contents of the         '301 Patent including all disclosures, embodiments and drawings         to the specification of the current application according to         MPEP 2163.07(b).     -   13. U.S. Pat. No. 9,326,362 B2 titled “TWO-LEVEL LED SECURITY         LIGHT WITH MOTION SENSOR” was issued on Apr. 26, 2016. The         applicant herein requests to incorporate the contents of the         '362 Patent including all disclosures, embodiments and drawings         to the specification of the current application according to         MPEP 2163.07(b).     -   14. U.S. Pat. No. 9,560,719 B2 titled “LED SECURITY LIGHT AND         LED SECURITY LIGHT CONTROL DEVICE THEREOF” was issued on Jan.         31, 2017. The applicant herein requests to incorporate the         contents of the '719 Patent including all disclosures,         embodiments and drawings to the specification of the current         application according to MPEP 2163.07(b).     -   15. U.S. Pat. No. 10,154,564 B2 titled “APP BASED FREE SETTING         METHOD FOR SETTING OPERATING PARAMETER OF SECURITY LIGHT” was         issued on Dec. 11, 2018. The applicant herein requests to         incorporate the contents of the '564 Patent including all         disclosures, embodiments and drawings to the specification of         the current application according to MPEP 2163.07(b).     -   16. U.S. Pat. No. 10,667,367 B2 titled “APP BASED FREE SETTING         METHOD FOR SETTING OPERATING PARAMETER OF SECURITY LIGHT” was         issued on May 26, 2020. The applicant herein requests to         incorporate the contents of the '367 Patent including all         disclosures, embodiments and drawings to the specification of         the current application according to MPEP 2163.07(b)

BACKGROUND 1. Technical Field

The present disclosure relates to a lighting apparatus, in particular, to a two-level security LED light with motion sensor

2. Description of Related Art

Lighting sources such as the fluorescent lamps, the incandescent lamps, the halogen lamps, and the light-emitting diodes (LED) are commonly found in lighting apparatuses for illumination purpose. Photoresistors are often utilized in outdoor lighting applications for automatic illuminations, known as the Photo-Control (PC) mode. Timers may be used in the PC mode for turning off the illumination or for switching to a lower level illumination of a lighting source after the lighting source having delivered a high level illumination for a predetermined duration, referred as the Power-Saving (PS) mode. Motion sensors are often used in the lighting apparatus for delivering full-power illumination thereof for a short duration when a human motion is detected, then switching back to the PS mode. Illumination operation controls such as auto-illumination in accordance with the background brightness detection, illumination using timer, illumination operation control using motion sensing results (e.g., dark or low luminous power to fully illuminated), and brightness control are often implemented by complex circuitries. In particular, the design and construction of LED drivers are still of a complex technology with high fabrication cost.

Therefore, how to develop a simple and effective design method on illumination controls such as enhancing contrast in illumination and color temperature for various types lighting sources, especially the controls for LEDs are the topics of the present disclosure.

SUMMARY

An exemplary embodiment of the present disclosure provides a two-level LED security light with motion sensor which may switch to high level illumination in the Power-Saving (PS) mode for a predetermined duration time when a human motion is detected thereby achieve warning purpose using method of electric current or lighting load adjustment. Furthermore, prior to the detection of an intrusion, the LED security light may be constantly in the low level illumination or cutoff to save energy.

An exemplary embodiment of the present disclosure provides a two-level LED security light including a power supply unit, a light sensing control unit, a motion sensing unit, an external control unit, a loading and power control unit, and a light-emitting unit. The light-emitting unit further includes one or a plurality of series- and/or parallel-connected LEDs; when the light sensing control unit detects that the ambient light is lower than a predetermined value, the loading and power control unit turns on the light-emitting unit to generate a high level or a low level illumination; when the light sensing control unit detects that the ambient light is higher than the predetermined value, the loading and power control unit turns off the light-emitting unit; when the motion sensing unit detects a human motion in the PS mode, the loading and power control unit increases the electric current that flows through the light-emitting unit so as to generate the high or full level illumination for a predetermined duration.

Another exemplary embodiment of the present disclosure provides a two-level LED security light including a power supply unit, a light sensing control unit, a motion sensing unit, an external control unit, a loading and power control unit, a light-emitting unit. The light-emitting unit includes a plurality of series- and/or parallel-connected LEDs. When the light sensing control unit detects that the ambient light is lower than a predetermined value, the loading and power control unit turns on a portion or all the LEDs of the light-emitting unit to generate a low level or a high level illumination; when the light sensing control unit detects that the ambient light is higher than the predetermined value, the loading and power control unit turns off all the LEDs in the light-emitting unit; when the motion sensing unit detects a human motion in the PS mode, the loading and power control unit turns on a plurality of LEDs in the light-emitting unit and generates the high or full level illumination for a predetermine duration. An electric current control circuit is integrated in the exemplary embodiment for providing constant electric current to drive the LEDS in the light-emitting unit.

One exemplary embodiment of the present disclosure provides a two-level LED security light including a power supply unit, a light sensing control unit, a motion sensing unit, an external control unit, a loading and power control unit, and a light-emitting unit. The light-emitting unit includes a phase controller and one or a plurality of parallel-connected alternating current (AC) LEDs. The phase controller is coupled between the described one or a plurality parallel-connected ACLEDs and AC power source. The loading and power control unit may through the phase controller control the average power of the light-emitting unit; when the light sensing control unit detects that the ambient light is lower than a predetermined value, the loading and power control unit turns on the light-emitting unit to generate a high level or a lower level illumination; when the light sensing control unit detects that the ambient light is higher than the predetermined value, the loading and power control unit turns off the light-emitting unit; when the motion sensing unit detects a human motion in the PS mode, the loading and power control unit increases the average power of the light-emitting unit thereby generates the high level illumination for a predetermine duration.

According to an exemplary embodiment of the present disclosure, a two-level LED security light includes a power supply unit, a light sensing control unit, a motion sensing unit, an external control unit, a loading and power control unit, and a light-emitting unit. The light-emitting unit includes X high wattage ACLEDs and Y low wattage ACLEDs connected in parallel. When the light sensing control unit detects that the ambient light is lower than a predetermined value, the loading and power control unit turns on the plurality of low wattage ACLEDs to generate a low level illumination; when the light sensing control unit detects that the ambient light is higher than a predetermined value, the loading and power control unit turns off the light-emitting unit; when the motion sensor detects an intrusion, the loading and power control unit turns on both the high wattage ACLEDs and the low wattage ACLEDs at same time thereby generates a high level illumination for a predetermine duration, wherein X and Y are of positive integers.

According to an exemplary embodiment of the present disclosure, a two-level LED security light with motion sensor includes a power supply unit, a light sensing control unit, a motion sensing unit, an external control unit, a loading and power control unit, and a light-emitting unit. The light-emitting unit includes a rectifier circuit connected between one or a plurality of parallel-connected AC lighting sources and AC power source. The loading and power control unit may through the rectifier circuit adjust the average power of the light-emitting unit. When the light sensing control unit detects that the ambient light is lower than a predetermined value, the loading and power control unit turns on the light-emitting unit to generate a low level illumination; when the light sensing control unit detects that the ambient light is higher than the predetermined value, the loading and power control unit turns off the light-emitting unit; when the motion sensing unit detects an intrusion, the loading and power control unit increases the average power of the light-emitting unit thereby generates a high level illumination for a predetermine duration. The rectifier circuit includes a switch parallel-connected with a diode, wherein the switch is controlled by the loading and power control unit.

To sum up, a two-level LED security light with motion sensor provided by an exemplary embodiment in the preset disclosure, may execute Photo-Control (PC) and Power-Saving (PS) modes. When operates in the PC mode, the lighting apparatus may auto-illuminate at night and auto turn off at dawn. The PC mode may generate a high or a low level illumination for a predetermined duration then automatically switch to the PS mode by a control unit to generate a low level or a cutoff illumination. When the motion sensor detects a human motion, the disclosed LED security light may immediate switch to the high or full level illumination for a short predetermined duration thereby achieve illumination or warning effect. After the short predetermined duration, the LED security light may automatically return to the low level illumination for saving energy. Although ACLEDs are used in some embodiments, the present invention is not limited in applying on the ACLEDs. It can be implemented with DC LEDs or DC LEDs in AC module such as LED bulbs incorporating with adequate power sources and circuitries which commonly known by a person of skill in the art.

In order to further understand the techniques, means and effects of the present disclosure, the following detailed descriptions and appended drawings are hereby referred, such that, through which, the purposes, features and aspects of the present disclosure can be thoroughly and concretely appreciated; however, the appended drawings are merely provided for reference and illustration, without any intention to be used for limiting the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

FIG. 1 schematically illustrates a block diagram of a two-level LED security light in accordance with an exemplary embodiment of the present disclosure.

FIG. 1A is an enhanced block diagrammed under FIG. 1 to specifically illustrate an embodiment of FIG. 1 for a two-level LED security light, wherein the loading and power control unit comprises a switching circuitry and a microcontroller, wherein the switching circuitry further comprises a bidirectional semiconductor switching device for controlling an average electric power to be delivered to the LED.

FIG. 1B is an enhanced block diagrammed under FIG. 1 to specifically illustrate an embodiment of FIG. 1 for a two-level LED security light, wherein the loading and power control unit comprises a switching circuitry and a microcontroller, wherein the switching circuitry further comprises a unidirectional semiconductor switching device for controlling an average electric power to be delivered to the LED.

FIG. 1C is an enhanced block diagrammed under FIG. 1 to specifically illustrate an embodiment of FIG. 1 for a two-level LED security light including a first set having N number LEDs and a second set having M number LEDs, wherein the loading and power control unit comprises a switching circuitry and a microcontroller, wherein the switching circuitry further comprises bidirectional semiconductor switching devices for controlling an average electric power to be delivered to the LED.

FIG. 1D is an enhanced block diagrammed under FIG. 1 to specifically illustrate an embodiment of FIG. 1 for a two-level LED security light including a first set having N number LEDs and a second set having M number LEDs, wherein the loading and power control unit comprises a switching circuitry and a microcontroller, wherein the switching circuitry further comprises unidirectional semiconductor switching devices for controlling an average electric power to be delivered to the LED.

FIG. 2A illustrates a schematic diagram of a two-level LED security light in accordance with the first exemplary embodiment of the present disclosure.

FIG. 2B graphically illustrates a timing waveform of a pulse width modulation (PWM) signal in accordance with the first exemplary embodiment of the present disclosure.

FIG. 3A illustrates a schematic diagram of a two-level LED security light in accordance with the second exemplary embodiment of the present disclosure.

FIG. 3B illustrates a schematic diagram of a two-level LED security light in accordance with the second exemplary embodiment of the present disclosure.

FIG. 4A illustrates a schematic diagram of a two-level LED security light in accordance with the third exemplary embodiment of the present disclosure.

FIG. 4B illustrates a timing waveform of two-level LED security light in accordance with the third exemplary embodiment of the present disclosure.

FIG. 5 illustrates a schematic diagram of a two-level LED security light in accordance with the third exemplary embodiment of the present disclosure.

FIG. 6 illustrates a schematic diagram of a two-level LED security light in accordance with the fourth exemplary embodiment of the present disclosure.

FIG. 7 illustrates a schematic diagram of a two-level LED security light in accordance with the fifth exemplary embodiment of the present disclosure.

FIGS. 8A, 8B, 8C and 8D schematically and respectively show V-I relationship charts (Forward Current vs. Forward Voltage) for a white LED chip from each of 4 different LED manufacturers.

FIG. 9 is a data sheet showing data of the minimum forward voltages and maximum forward voltages collected from various LED manufacturers for generating a designated constant forward current to produce a required lumens output.

DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Reference is made in detail to the exemplary embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or alike parts.

First Exemplary Embodiment

Refer to FIG. 1, which schematically illustrates a block diagram of a two-level LED security light in accordance with the first exemplary embodiment of the present disclosure. A two-level LED security light (herein as the lighting apparatus) 100 includes a power supply unit 110, a light sensing control unit 120, a motion sensing unit 130, an external control unit 160, a loading and power control unit 140, and a light-emitting unit 150. The power supply unit 110 is used for supplying power required to operate the system, wherein the associated structure includes the known AC/DC voltage converter. The light sensing control unit 120 may be a photoresistor, which may be coupled to the loading and power control unit 140 for determining daytime or nighttime in accordance with the ambient light. The motion sensing unit 130 may be a passive infrared sensor (PIR), which is coupled to the loading and power control unit 140 and is used to detect intrusions. When a person is entering a predetermined detection zone of the motion sensing unit 130, a sensing signal thereof may be transmitted to the loading and power control unit 140. The external control unit 160 is coupled to the loading and power control unit 140 for setting various operating parameters of a security light including at least a time length setting (a time setting unit) for various illumination modes, at least a light intensity setting for various illumination modes and switching between illumination modes. The external control unit 160 may be configured with a push button, a touch sensor, a voltage divider, a power interruption detection circuitry or a wireless remote control receiver for processing signals interpretable by the loading and power control unit 140.

The loading and power control unit 140 which is coupled to the light-emitting unit 150 may be implemented by a microcontroller. The loading and power control unit 140 may control the illumination levels of the light-emitting unit 150 in accordance with the sensing signal outputted by the light sensing control unit 120 and the motion sensing unit 130. The light-emitting unit 150 may include a plurality of LEDs and switching components. The loading and power control unit 140 may control the light-emitting unit 150 to generate at least two levels of illumination variations.

When the light sensing control unit 120 detects that the ambient light is lower than a predetermined value (i.e., nighttime), the loading and power control unit 140 executes the Photo-Control (PC) mode by turning on the light-emitting unit 150 to generate a high level illumination for a predetermined duration then return to a low level illumination for Power-Saving (PS) mode. When the light sensing control unit 120 detects that the ambient light is higher than a predetermined value (i.e., dawn), the loading and power control unit 140 turns off the light-emitting unit 150. In the PS mode, when the motion sensing unit 130 detects a human motion, the loading and power control unit 140 may increase the electric current which flow through the light-emitting unit 150 to generate the high level illumination for a short predetermined duration. After the short predetermined duration, the loading and power control unit 140 may automatically lower the electric current that flow through the light-emitting unit 150 thus have the light-emitting unit 150 return to low level illumination for saving energy.

Refer to 2A, which illustrates a schematic diagram of a two-level LED security light in accordance with the first exemplary embodiment of the present disclosure. The light sensing control unit 120 may be implemented by a light sensor 220; the motion sensing unit 130 may be implemented by a motion sensor 230; the loading and power control unit 140 may be implemented by a microcontroller 240. The light-emitting unit 250 includes three series-connected LEDs L1˜L3. The LEDs L1˜L3 is connected between a DC source and a transistor Q1, wherein the DC source may be provided by the power supply unit 110. The transistor Q1 may be an N-channel metal-oxide-semiconductor field-effect-transistor (NMOS). The transistor Q1 is connected between the three series-connected LEDs L1˜L3 and a ground GND. The loading and power control unit 140 implemented by the microcontroller 240 may output a pulse width modulation (PWM) signal to the gate of transistor Q1 to control the average electric current. It is worth to note that the electric components depicted in FIG. 2A only serves as an illustration for the exemplary embodiment of the present disclose and hence the present disclosure is not limited thereto.

Refer to FIG. 2B concurrently, which graphically illustrates a timing waveform of a pulse width modulation (PWM) signal in accordance with the first exemplary embodiment of the present disclosure. In the PC mode, the PWM signal may be used to configure the transistor Q1 to have the conduction period T_(on) being longer than the cut-off period T_(off). On the other hand in the PS mode, the PWM signal may configure the transistor Q1 to have the conduction period T_(on) being shorter than the cut-off period T_(off). In comparison of the illumination levels between the PC and PS modes, as the conduction period T_(on) of transistor Q1 being longer under the PC mode, therefore have higher average electric current driving the light-emitting unit 250 thereby generate high illumination, which may be classified as the high level illumination; whereas as the conduction period T_(on) of transistor Q1 is shorter in the PS mode, therefore have lower average electric current driving the light-emitting unit 250 thereby generate low illumination, which may be classified as the low level illumination.

The microcontroller 240 turns off the light-emitting unit 250 during the day and activates the PC mode at night by turning on the light-emitting unit 250 to generate the high level illumination for a short predetermined duration then return to the low level illumination thereby entering the PS mode. When the motion sensor 230 detects a human motion in the PS mode, the light-emitting unit 250 may switch to the high level illumination for illumination or warning application. The light-emitting unit 250 may return to the low level illumination after maintaining at the high level illumination for a short predetermined duration to save energy.

In addition, the microcontroller 240 is coupled to a time setting unit 260, wherein the time setting unit 260 may allow the user to configure the predetermined duration associated with the high level illumination in the PC mode, however the present disclosure is not limited thereto. The time setting unit is a type of external control units designed to process various external control signals interpretable by the controller for setting at least a time length setting for various illumination modes.

Second Exemplary Embodiment

Refer again to FIG. 1, wherein the illumination variations of the light-emitting unit 150 may be implemented through the number of light-source loads being turned on to generate more than two levels of illumination. The lighting apparatus 100 in the instant exemplary embodiment may be through turning on a portion of LEDs or all the LEDs to generate a low and a high level of illuminations.

Refer to FIG. 3A concurrently, which illustrates a schematic diagram of a two-level LED security light 100 in accordance with the second exemplary embodiment of the present disclosure. The main difference between FIG. 3A and FIG. 2A is in the light-emitting unit 350, having three series-connected LEDs L1˜L3 and NMOS transistors Q1 and Q2. The LEDs L1˜L3 are series connected to the transistor Q1 at same time connected between the DC source and a constant electric current control circuit 310. Moreover, transistor Q2 is parallel connected to the two ends associated with LEDs L2 and L3. The gates of the transistors Q1 and Q2 are connected respectively to a pin PC and a pin PS of the microcontroller 240. The constant electric current control circuit 310 in the instant exemplary embodiment maintains the electric current in the activated LED at a constant value, namely, the LEDs L1˜L3 are operated in constant-current mode.

Refer to FIG. 3A, the pin PC of the microcontroller 240 controls the switching operations of the transistor Q1; when the voltage level of pin PC being either a high voltage or a low voltage, the transistor Q1 may conduct or cut-off, respectively, to turn the LEDs L1˜L3 on or off. The pin PS of the microcontroller 240 controls the switch operations of the transistor Q2, to form two current paths 351 and 352 on the light-emitting unit 350. When the voltage at the pin PS of the microcontroller 240 is high, the transistor Q2 conducts, thereby forming the current path 351 passing through the LED L1 and the transistor Q2; when the voltage at the pin PS being low, the transistor Q2 cuts-off, thereby forming the current path 352 passing through all the LEDs L1˜L3. The microcontroller 240 may then control the switching operation of the transistor Q2 to turn on the desired number of LEDs so as to generate a high or a low level illumination.

When light sensor 220 detects that the ambient light is higher than a predetermined value, the microcontroller 240 through the pin PC outputs a low voltage, which causes the transistor Q1 to cut-off and turns off all the LEDs L1˜L3 in the light-emitting unit 350. Conversely, when the light sensor 220 detects that the ambient light is lower than the predetermined value, the microcontroller 240 activates the PC mode, i.e., outputting a high voltage from pin PC and a low voltage from pin PS, to activate the transistor Q1 while cut-off the transistor Q2, thereby forming the current path 352, to turn on the three LEDs L1˜L3 in the light-emitting unit 350 so as to generate the high level illumination for a predetermined duration. After the predetermined duration, the microcontroller 240 may switch to the PS mode by having the pin PC continue outputting a high voltage and the pin PS outputting a high voltage, to have the transistor Q2 conducts, thereby forming the current path 351. Consequently, only the LED L1 is turned on and the low level illumination is generated.

When the motion sensor detects a human motion in the PS mode, the pin PS of the microcontroller 240 temporarily switches from the high voltage to a low voltage, to have the transistor Q2 temporarily cuts-off thus forming the current path 352 to activate all the LEDs in the light-emitting unit 350, thereby temporarily generates the high level illumination. The light-emitting unit 350 is driven by a constant electric current, therefore the illumination level generated thereof is directly proportional to the number of LEDs activated. FIG. 3B illustrates another implementation for FIG. 3A, wherein the relays J1 and J2 are used in place of NMOS transistors to serve as switches. The microcontroller 240 may control the relays J2 and J1 through regulating the switching operations of the NPN bipolar junction transistors Q4 and Q5. Moreover, resistors R16 and R17 are current-limiting resistors.

In the PC mode, the relay J1 being pull-in while the relay J2 bounce off to have constant electric current driving all the LEDs L1˜L3 to generate the high level illumination; in PS mode, the relays J1 and J2 both pull-in to have constant electric current only driving the LED L1 thus the low level illumination may be thereby generated. Furthermore, when the motion sensor 230 detects a human motion, the pin PS of the microcontroller 240 may temporarily switch from high voltage to low voltage, forcing the relay J2 to temporarily bounce off and the relay J1 pull-in so as to temporarily generate the high level illumination.

The LED L1 may adopt a LED having a color temperature in a range between 2000K and 3000K, while the LEDs L2 and L3 may adopt LEDs having a color temperature between 4000K and 6500K in order to increase the contrast between the high level and the low level illuminations. The number of LEDs included in the light-emitting unit 350 may be more than three, for example five or six LEDs. The transistor Q2 may be relatively parallel to the two ends associated with a plurality of LEDs to adjust the illumination difference between the high and the low illumination levels. Additionally, the light-emitting unit 350 may include a plurality of transistors Q2, which are respectively coupled to the two ends associated with each LED to provide more lighting variation selections. The microcontroller 240 may decide the number of LEDs to turn on in accordance to design needs at different conditions. Based on the explanation of the aforementioned exemplary embodiment, those skills in the art should be able to deduce other implementation and further descriptions are therefore omitted.

Third Exemplary Embodiment

Refer back to FIG. 1, wherein the light-emitting unit 150 may include a phase controller and one or more parallel-connected alternating current (AC) LEDs. The phase controller is coupled between the described one or more parallel-connected ACLEDs and AC power source. The loading and power controller 140 in the instant exemplary embodiment may through the phase controller adjust the average power of the light-emitting unit 150 so as to generate variations in the low level and the high level illuminations.

Refer to FIG. 4A, which illustrates a schematic diagram of a two-level LED security light 100 in accordance with the third exemplary embodiment of the present disclosure. The main difference between FIG. 4A and FIG. 3 is in that the light-source load is an ACLED, which is coupled to the AC power source, and further the light-emitting unit 450 includes a phase controller 451. The phase controller 451 includes a bi-directional switching device 452, here, a triac, a zero-crossing detection circuit 453, and a resistor R. The microcontroller 240 turns off the light-emitting unit 450 when the light sensor 220 detects that the ambient light is higher than a predetermined value. Conversely, when the light sensor 220 detects that the ambient light is lower than the predetermined value, the microcontroller 240 activates the PC mode by turning on the light-emitting unit 450. In the PC mode, the microcontroller 240 may select a control pin for outputting a pulse signal which through a resistor R triggers the triac 452 to have a large conduction angle. The large conduction angle configures the light-emitting unit 450 to generate a high level illumination for a predetermined duration. Then the microcontroller 240 outputs the pulse signal for PS mode through the same control pin to trigger the triac 452 to have a small conduction angle for switching the light-emitting unit 450 from the high level illumination to the low level illumination of the PS mode. Moreover, when the motion sensor 230 (also called motion sensing unit) detects a human motion in the PS mode, the microcontroller 240 temporarily outputs the PC-mode pulse signal through the same control pin to have the light-emitting unit 450 generated the high level illumination for a short predetermined duration. After the short predetermined duration, the light-emitting unit 450 returns to the low level illumination.

In the illumination control of the ACLED, the microcontroller 240 may utilize the detected zero-crossing time (e.g., the zero-crossing time of an AC voltage waveform) outputted from the zero-crossing detection circuit 453 to send an AC synchronized pulse signal thereof which may trigger the triac 452 of the phase controller 451 thereby to change the average power input to the light-emitting unit 450. As the ACLED has a cut-in voltage V_(t) for start conducting, thus if the pulse signal inaccurately in time triggers the conduction of the triac 452, then the instantaneous value of AC voltage may be lower than the cut-in voltage V_(t) of ACLED at the trigger pulse. Consequently, the ACLED may result in the phenomenon of either flashing or not turning on. Therefore, the pulse signal generated by the microcontroller 240 must fall in a proper time gap behind the zero-crossing point associated with the AC sinusoidal voltage waveform.

Supposing an AC power source having a voltage amplitude V_(m) and frequency f, then the zero-crossing time gap t_(D) of the trigger pulse outputted by the microcontroller 240 should be limited according to t_(o)<t_(D)<½f−t_(o) for a light-source load with a cut-in voltage V_(t), wherein t_(o)=(½πf)sin⁻¹(V_(t)/V_(m)). The described criterion is applicable to all types of ACLEDs to assure that the triac 452 can be stably triggered in both positive and negative half cycle of the AC power source. Take ACLED with V_(t)(rms)=80V as an example, and supposing the V_(m)(rms)=110V and f=60 Hz, then t_(o)=2.2 ms and (½f)=8.3 ms may be obtained. Consequently, the proper zero-crossing time gap t_(D) associated with the phase modulation pulse outputted by the microcontroller 240 which lagged the AC sinusoidal voltage waveform should be designed in the range of 2.2 ms<t_(D)<6.1 ms.

Refer to FIG. 4B, which illustrates a timing waveform of the two-level LED security light in accordance with the third exemplary embodiment of the present disclosure. Waveforms (a)˜(d) of FIG. 4B respectively represent the AC power source, the output of the zero-crossing detection circuit 453, the zero-crossing delay pulse at the control pin of the microcontroller 240, and the voltage waveform across the two ends of the ACLED in the light-emitting unit 450. The zero-crossing detection circuit 453 converts the AC voltage sinusoidal waveform associated with the AC power source to a symmetric square waveform having low and high voltage levels as shown in FIG. 4B(b). At the zero-crossing point of the AC voltage sinusoidal wave, the symmetric square waveform may transit either from the low voltage level to the high voltage level or from the high voltage level to the low voltage level. Or equivalently, the edge of the symmetric square waveform in the time domain corresponds to the zero-crossing point of the AC voltage sinusoidal waveform. As shown in FIG. 4B(c), the microcontroller 240 outputs a zero-crossing delay pulse in correspondence to the zero-crossing point of the AC sinusoidal waveform in accordance with the output waveform of the zero-crossing detection circuit 453. The zero-crossing delay pulse is relative to an edge of symmetric square waveform behind a time gap t_(D) in the time domain. The t_(D) should fall in a valid range, as described previously, to assure that the triac 452 can be stably triggered thereby to turn on the ACLED. FIG. 4B(d) illustrates a voltage waveform applied across the two ends associated with the ACLED. The illumination level of the light-emitting unit 450 is related to the conduction period t_(on) of the ACLED, or equivalently, the length t_(on) is directly proportional to the average power inputted to the ACLED. The difference between the PC mode and the PS mode being that in the PC mode, the ACLED has longer conduction period, thereby generates the high level illumination; whereas in the PS mode, the ACLED conduction period is shorter, hence generates the low level illumination.

Refer to FIG. 5, which illustrates a schematic diagram of a two-level LED security light 100 in accordance with the third exemplary embodiment of the present disclosure. The light-emitting unit 550 of the lighting apparatus 100 includes an ACLED1, an ACLED2, and a phase controller 551. The phase controller 551 includes triacs 552 and 553, the zero-crossing detection circuit 554 as well as resistors R1 and R2. The light-emitting unit 550 of FIG. 5 is different from the light-emitting unit 450 of FIG. 4 in that the light-emitting unit 550 has more than one ACLEDs and more than one bi-directional switching devices. Furthermore, the color temperatures of the ACLED1 and the ACLED2 may be selected to be different.

In the exemplary embodiment of FIG. 5, the ACLED1 has a high color temperature, and the ACLED2 has a low color temperature. In the PC mode, the microcontroller 240 uses the phase controller 551 to trigger both ACLED1 and ACLED2 to conduct for a long period, thereby to generate the high level illumination as well as illumination of mix color temperature. In the PS mode, the microcontroller 240 uses the phase controller 551 to trigger only the ACLED2 to conduct for a short period, thereby generates the low level illumination as well as illumination of low color temperature. Moreover, in the PS mode, when the motion sensor 230 detects a human motion, the microcontroller 240 may through the phase controller 551 trigger the ACLED1 and ACLED2 to conduct for a long period. Thereby, it may render the light-emitting unit 450 to generate the high level illumination of high color temperature and to produce high contrast in illumination and hue, for a short predetermined duration to warn the intruder. Consequently, the lighting apparatus may generate the high level or the low level illumination of different hue. The rest of operation theories associated with the light-emitting unit 550 are essentially the same as the light-emitting unit 450 and further descriptions are therefore omitted.

Fourth Exemplary Embodiment

Refer to FIG. 6, which illustrates a schematic diagram of a two-level LED security light 100 in accordance with the fourth exemplary embodiment of the present disclosure. The light-emitting unit 150 of FIG. 1 may be implemented by the light-emitting unit 650, wherein the light-emitting unit 650 includes three ACLED1˜3 having identical luminous power as well as switches 651 and 652. In which, switches 651 and 652 may be relays. The parallel-connected ACLED1 and ACLED2 are series-connected to the switch 652 to produce double luminous power, and of which the ACLED3 is parallel connected to, to generate triple luminous power, and of which an AC power source is further coupled to through the switch 651. Moreover, the microcontroller 240 implements the loading and power control unit 140 of FIG. 1. The pin PC and pin PS are respectively connected to switches 651 and 652 for outputting voltage signals to control the operations of switches 651 and 652 (i.e., open or close).

In the PC mode, the pin PC and pin PS of the microcontroller 240 control the switches 651 and 652 to be closed at same time. Consequently, the ACLED1˜3 are coupled to the AC power source and the light-emitting unit 650 may generate a high level illumination of triple luminous power. After a short predetermined duration, the microcontroller 240 returns to PS mode. In which the switch 651 is closed while the pin PS controls the switch 652 to be opened, consequently, only the ACLED3 is connected to AC power source, and the light-emitting unit 650 may thus generate the low level illumination of one luminous power. In the PS mode, when the motion sensor 230 detects a human motion, the microcontroller 240 temporarily closes the switch 652 to generate high level illumination with triple luminous power for a predetermined duration. After the predetermined duration, the switch 652 returns to open status thereby to generate the low level illumination of one luminous power. The lighting apparatus of FIG. 6 may therefore through controlling switches 651 and 652 generate two level illuminations with illumination contrast of at least 3 to 1.

The ACLED1 and ACLED2 of FIG. 6 may be high power lighting sources having a color temperature in a range between 4000K and 6500K. The ACLED3 may be a low power lighting source having a color temperature between 2000K and 3000K. Consequently, the ACLED may generate two levels of illuminations with high illumination and hue contrast without using a zero-crossing detection circuit.

Fifth Exemplary Embodiment

Refer to FIG. 7, which illustrates a schematic diagram of a two-level LED security light in accordance with the fifth exemplary embodiment of the present disclosure. The light-emitting unit 750 of FIG. 7 is different from the light-emitting unit 640 of FIG. 6 in that the ACLED3 is series-connected to a circuit with a rectified diode D and a switch 753 parallel-connected together, and of which is further coupled through a switch 751 to AC power source. When the switch 753 closes, the AC electric current that passes through the ACLED3 may be a full sinusoidal waveform. When the switch 753 opens, the rectified diode rectifies the AC power, thus only one half cycle of the AC electric current may pass through the ACLED, consequently the luminous power of ACLED3 is cut to be half.

The pin PS of the microcontroller 240 synchronously controls the operations of switches 752 and 753. If the three ACLED1˜3 have identical luminous power, then in the PC mode, the pin PC and pin PS of the microcontroller 240 synchronously close the switches 751˜753 to render ACLED1˜3 illuminating, thus the light-emitting unit 750 generates a high level illumination which is three-times higher than the luminous power of a single ACLED. When in the PS mode, the microcontroller 240 closes the switch 751 while opens switches 752 and 753. At this moment, only the ACLED3 illuminates and as the AC power source is rectified by the rectified diode D, thus the luminous power of ACLED3 is half of the AC power source prior to the rectification. The luminous power ratio between the high level and the low level illuminations is therefore 6 to 1. Consequently, strong illumination contrast may be generated to effectively warn the intruder.

It should be noted that the light-emitting unit in the fifth exemplary embodiment is not limited to utilizing ACLEDs. In other words, the light-emitting unit may include any AC lighting sources such as ACLEDs, incandescent lamps, or fluorescent lamps.

When the light source of the light-emitting unit 150 is confined to the use of an LED load, the compliance and satisfaction of a voltage operating constraint attributable to the unique electrical characteristics of the LED load is vital to a successful performance of an LED lighting device. Any LED lighting device failing to comply with the voltage operating constraint of the unique electrical characteristics is bound to become a trouble art. This is because the LED as a kind of solid state light source has completely different electrical characteristics for performing light emission compared with conventional light source such as incandescent bulbs or fluorescent bulbs.

For instance, for a white light LED or blue light LED there exists a very narrow voltage domain ranging from a threshold voltage at around 2.5 volts to a maximum operating voltage at around 3.5 volts, which allows the LEDs to operate adequately and safely; in other words, when a forward voltage imposed on the LED is lower than the threshold voltage, the LED is not conducted and therefore no light is emitted, when the forward voltage exceeds the maximum operating voltage, the heat generated by a forward current could start damaging the construction of the LED. Therefore, the forward voltage imposed on the LED is required to operate between the threshold voltage and the maximum operating voltage. In respect to the LED load of the light-emitting unit 150, the cut-in voltage V_(t) of ACLEDs is technically also referred to as the threshold voltage attributable to PN junctions manufactured in LEDs. More specifically, the LED is made with a PN junction semiconductor structure inherently featured with three unique electrical characteristics, the first characteristic is one-way electric conduction through the PN junction fabricated in the LED, the second electrical characteristic is a threshold voltage V_(th) required to trigger the LED to start emitting light and the third electrical characteristic is a maximum operating voltage V_(max) allowed to impose on the LED to avoid a thermal runaway to damage or burn out the semiconductor construction of the LED. The described cut-in voltage V_(t) has the same meaning as the above mentioned threshold voltage V_(th) which is a more general term to be used for describing the second electrical characteristic of a PN junction semiconductor structure. Also, because the cut-in voltage V_(t) is specifically tied to forming a formula to transform the threshold voltage into a corresponding time phase of AC power for lighting control, it is necessary to use the term V_(th) as a neutral word for describing the LED electrical characteristics to avoid being confused with the specific application for ACLED alone. Additionally, it is to be clarified that the term Vm is related to the amplitude of the instant maximum voltage of an AC power source which has nothing to do with the third electrical characteristic V_(max) of an LED load.

An LED chip is a small piece of semiconductor material with at least one LED die manufactured inside the semiconductor material. A plurality of LED dies may be manufactured and packaged inside an LED chip for different levels of wattage specification to meet different illumination need. The LED die can also be designed with a larger size of PN junction such that a higher forward current can be generated for higher wattage applications without damaging the LED structure but in such case less quantity of LED dies can be produced from each wafer. For each LED chip designed with a different level of wattage specification there always exists a narrow voltage domain V_(th)<V<V_(max), wherein V is a voltage across each LED chip, wherein V_(th) is the threshold voltage to enable the LED chip to start emitting light and V_(max) is the maximum operating voltage imposed on the LED chip to avoid the LED chip from being damaged or burned out by the heat generated by the high operating voltage at V_(max). Such voltage constraints are attributable to the different semiconductor materials used, different manufacturing and packaging processes employed. Although the values of threshold voltage and maximum operating voltage may vary within a narrow dispersion of distribution among LEDs produced from different manufacturers, they can be represented by some reference values which are learned from cumulation of manufacturing and practicing experiences by the LED manufacturers. The reference values are necessary and useful to serve as guidelines for designing LED driver to ensure an LED voltage bin selected does comply with the narrow voltage domain V_(th)<V<V_(max) for generating a constant forward current to produce a designated light intensity.

LED dies are batch-produced by wafers and each wafer is designed to produce a large quantity of LED dies which may respectively require different forward voltages within a narrow distribution range for generating a designated forward current. For instance if a batch of #2835 0.5 watt LED dies are used to generate a designated forward current at 150 mA, among the batch of LED dies produced from the same manufacturer, there exists a distribution range of required forward voltages from 2.9 volts (Minimum Forward Voltage, V_(FMIN)) to 3.3 volts (Maximum Forward Voltage, V_(FMAX)) to generate the same designated forward current, the batch of LED dies is further divided and grouped by the manufacturer into a few voltage bins with each voltage bin having a much smaller subrange of forward voltages bounded by a bin minimum forward voltage V_(BMIN) and a bin maximum forward voltage V_(BMAX) for generating the same forward current. For instance, the distribution range may be divided into four voltage bins with a first bin accommodating a forward voltage subrange from 2.9 volts to 3.0 volts, a second voltage bin accommodating a forward voltage subrange from 3.0 volts to 3.1 volts, a third bin accommodating a forward voltage subrange from 3.1 volts to 3.2 volts, and a fourth bin accommodating a forward voltage subrange from 3.2 volts to 3.3 volts. The LED dies grouped in the first bin belong to the most efficient LED dies produced from the wafer as they only need lowest forward voltages to generate same designated forward current, then followed by the second bin, then followed by the third bin and then the fourth bin being the least efficient LED dies produced by the wafer as they need highest forward voltages to generate same forward current. LED manufacturers sell LED dies by voltage bins with each voltage bin containing a plurality of LED dies which requires different forward voltages to generate a designated forward current for emitting light. Such division of LED dies by voltage bins is necessitated in order to minimize a volatility of forward voltages for generating a designated constant forward current. Otherwise, a large swing of forward voltages between the maximum forward voltage V_(FMAX) and the minimum forward voltage V_(FMIN) could easily cause an LED load fail because the V_(FMAX) required for driving the least efficient LED die(s) could be too close to or exceeding the maximum operating voltage V_(max), which could cause the LED load damaged or burned out since all LED dies are electrically connected in series. In other words without the division of forward voltages by voltage bins it would be difficult to comply with the constraints of V_(th)<V<V_(max). Similar bin arrangements are also applicable to color temperature performance and brightness performance for LED dies produced from a wafer. Generally speaking, LED bins with lower forward voltages can be priced higher than LED bins with higher forward voltages. Both the minimum forward voltage V_(BMIN) and the maximum forward voltage V_(BMAX) in each bin selected are required to comply with voltage operating constraint V_(th)<V<V_(max), wherein V is a variable of forward voltage in the subrange of the voltage bin selected, wherein V_(th) is a reference value of a threshold voltage required to trigger each LED in the batch of LED dies produced from the manufacturer to emit light and V_(max) is a reference value of a maximum operating voltage across each LED in the batch of LEDs from the manufacturer at which the LED is vulnerable to a thermal damage. Please notice V_(BMIN) and V_(BMAX) respectively represent the lowest forward voltage and the highest forward voltage among the batch of LED dies for a selected voltage bin produced by the LED manufacturer to generate a designated constant forward current for outputting a designated lumens whereas the threshold voltage V_(th) and the maximum operating voltage V_(max) respectively refer to a minimum forward voltage to trigger any LED die to start generating a forward current and a maximum forward voltage at which the LED die is possibly vulnerable to a thermal damage.

When an LED load of an LED lighting device is configured with a plurality of N pieces of LEDs electrically connected in series or N sets of in parallel connected LEDs electrically connected in series, a working voltage V_(N) imposed on the LED load is therefore required to be in a range between N×V_(th) and N×V_(max), namely, N×V_(th)<V_(N)<N×V_(max).

When the plurality of LEDs are white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, a reference value of the threshold voltage V_(th) is estimated at 2.5 volts and a reference value of the maximum operating voltage is estimated at 3.5 volts subject to an operating condition that a temperature of each LED connecting pin is controlled at or below 80 degrees centigrade thru an adequate design of a heat sink, therefore the voltage V across each LED of the N pieces of LEDs is thereby required to comply with an operating constraint of 2.5 volts<V<3.5 volts and the working voltage V_(N) imposed on the LED load is thereby confined in a domain expressed by N×2.5 volts<V_(N)<N×3.5 volts. For any LED lighting device comprising an LED load it is required that the LED load in conjunction with an adequate level of power source is configured with a combination of in series and or in parallel connections of LED chips such that the electric current passing through each LED chip of the LED load remains at an adequate level such that a voltage V across each LED chip complies with the voltage operating constraint of V_(th)<V<V_(max) featuring electrical characteristics of the LED chip and the working voltage V_(N) across the LED load configured with N number of LED chips connected in series complies with an operating constraint of N×V_(th)<V_(N)<N×V_(max).

FIGS. 8A, 8B, 8C and 8D comprises 4 drawings schematically and respectively showing a V-I relationship chart (Forward Current vs. Forward Voltage) for a #2835 0.5 watt white light LED chip from each of 4 different LED manufacturers; as can be seen from the chart when a forward voltage V is below a threshold voltage at around 2.5 volts, the LED chip is essentially not conducted so a forward current I is essentially equal to zero, as the forward voltage exceeds 2.5 volts the LED chip is activated to generate a current flow to emit light, as the forward voltage continues to increase, the forward current I increases exponentially at an accelerated pace, at a maximum forward voltage at around 3.5 volts the forward current I becomes 250 mA or higher, which could generates a heat that could start damaging the PN junction of the LED chip (Cree J Series 2835 LEDs). While an LED die can be designed with a larger PN junction for operating a higher level of forward current for generating a higher lumens output, it is to be noticed the operating constraint of forward voltage has little to do with the dimensions of PN junction designed, therefore V_(th)<V<V_(max) remains effective and necessary as such forward voltage constraint is attributable to the materials used in making the phosphor based white light LED. Although an LED is a current driven light emitter, it is to be recognized that ultimately it is the voltage that generates the current flow to drive the LED to emit light, no voltage no light emission so to speak. As shown in the V-I relationship chart, when the forward voltage is increased from 2.5 volts to 3.5 volts for the Cree 2835 LED, the corresponding forward current is substantially increased from 0 to 250 mA. Such feature of a high performance leverage of a large variation of forward current against a small variation of forward voltage makes it inappropriate to use a voltage as a variable to accurately control lumens output of an LED load. Instead, it is more appropriate to use and to vary the constant current to operate the LED load. There are at least two reasons which support the use of the constant current source for operating the LED load: first, when a forward voltage varies by a 5% tolerance the forward current could vary in multiple like 40% to 50% for example. This could cause some LED(s) damaged in the LED load since we all know the LED dies from the same wafer have different forward voltages for generating same forward current; second, when the forward voltage varies a 5% tolerance the forward current could vary in multiple to result into a 40% to 50% fluctuation in light intensity which obviously cannot be accepted by consumers. A constant current source is always configured with a voltage power source to work in conjunction with a constant current control circuit which comprises a feedback circuit to provide a current information to the controller of the voltage power source for continuously adjusting output voltage level such that the current is kept constant.

In the semiconductor industry including the LED, the values of electrical parameters which characterize the natural inherent properties of semiconductor materials often are not precise or fixed, they always come with a range of distribution with a narrow dispersion, namely a reference range. For semiconductor devices in different categories of applications such as silicon based diode versus compound semiconductors based LED such as GaAs or GaP, their respective values of electrical parameters have very different distribution ranges though they all have the common features of having to operate in a conduction period between different threshold voltages and different maximum operating voltages. For semiconductor devices in the same category of application, the values are also different among different manufacturers though the variation ranges are much smaller and more predictable. Even the same white light LED dies produced from the same wafer there still exists a small yet predictable variation range of distribution as disclosed in the above descriptions for Cree 2835 LED about the structure of the LED voltage bins. They are just the natural inherent properties of semiconductor materials that the electrical parameters of semiconductor materials are impossibly represented by fixed values instead they always come with ranges of probability distribution with a narrow dispersion. With the above explanations being disclosed it is necessary to interpret or define the threshold voltage being a narrow interval comprised of a reference value plus a small tolerance e.g. 5% to 10%, or the reference ranges, therefore the reference value of threshold voltage at 2.5 volts with 5% tolerance would mean 2.5 volts+5%×2.5 volts=2.625 volts and the reference value of maximum operating voltage at 3.5 volts would mean 3.5 volts-5%×3.5 volts=3.325 volts, therefore the forward voltage V is interpretably operated as 2.5 volts<2.625 volts≤V≤3.325 volts<3.5 volts.

FIG. 9 is a data sheet showing data of the minimum forward voltages and maximum forward voltages for generating a designated forward current for LED dies produced from various LED manufacturers. They are the variation ranges of forward voltages formed by pairs of Maximum Forward Voltage and Minimum Forward Voltage of LED dies manufactured by different manufacturers before being divided and grouped into different voltage bins. Such variation ranges formed by each V_(FMAX) and V_(FMIN) are also required to satisfy the operating formula 2.5 volts<V<3.5 volts.

In summary, the compliance of voltage operating constraint V_(th)<V<V_(max) featuring electrical characteristics of an LED chip is a critical technology for ensuring a normal performance of the LED load. Failing to comply with such voltage operating constraint can quickly age or seriously damage the semiconductor structure of the LED chip with a consequence of quick lumens depreciation of the LED bulbs and the product lifetime being substantially shortened, which will be unacceptable to the consumers.

The compliance of the operating constraint V_(th)<V<V_(max) is a necessary matter for any LED lighting device though it is not an obvious matter as it requires complicated technologies to calculate and coordinate among an adequate level of power source, a control circuitry and a non-linear V-I relationship of light-emitting load. For conventional lighting load such as incandescent bulb there exists no such operating constraint. This is why in the past years there had been many consumers complaining about malfunction of LED bulbs that the consumers were frustrated with the fast depreciation of lumens output and substantially shortened product lifetime of the LED bulbs purchased and used. A good example was a law suit case filed by the Federal Trade Commission on Sep. 7, 2010 (Case No. SACV10-01333 JVS) for a complaint against a leading lighting manufacturer for marketing deceptive LED lamps and making false claims with respect to the life time of their LED lamps and a huge amount of monetary relief was claimed with the Court in the complaint.

To further elaborate the importance of the constraints of operating formula V_(th)<V<V_(max), it is necessary for the applicant to describe the following system operating flow chart to explain how the operating formula plays its indispensable role in LED driver design such that an LED light so designed is always ensured of being operated in a safety range when energized and the LED light can be expected as an energy saving and long lasting light source;

System Flowchart for Designing an LED Driver of an LED Light:

-   -   a) Step 1 Determine a maximum lumens output before a lumens loss         by the light diffuser. For example, use a maximum lumens         L_(max)=3200 lumens.     -   b) Step 2 Select an LED die capable of generating X lumens, e.g.         X=80 lumens and then calculate a minimum quantity Q_(min) of the         LED dies for configuring the light emitting unit.         Q_(min)=3200/80=40 LEDs.     -   c) Step 3 Obtain the corresponding value of the forward current         I which generates the required lumens (e.g. 80 lumens) from the         LED manufacturer's data pool.     -   d) Step 4 Select and obtain an LED voltage bin comprising a         plurality of LED dies with different forward voltages able to         produce same forward current on the V-I relationship curves to         generate same lumens output (e.g. 80 lumens). The selected         voltage bin comprising a plurality of LED dies with different         forward voltages form a bin voltage domain bounded by the         minimum forward voltage V_(BMIN) and the maximum forward voltage         V_(BMAX).     -   e) Step 5 At this stage both the LED manufacturer and the         circuit designer of the LED light are obliged to carefully check         both V_(BMIN) and V_(BMAX) are in full compliance with the         operating constraints of 2.5 volts<V<3.5 volts, wherein V is a         variable of forward voltages in the voltage domain bounded by         V_(BMIN) and V_(BMAX), or equivalently V_(th)<V_(BMIN) and         V_(BMAX)<V_(max).         -   If V is within the domain between 2.5 volts and 3.5 volts,             the selected LED voltage bin is acceptable. If V is outside             of the domain then the LED voltage bin selected is not             acceptable because the LED light would fail its performance             as disclosed in the specification and claims. Under such             circumstances either the lumens output level is to be             reduced until the corresponding forward voltage falls in the             domain or a different LED die which can satisfy the voltage             operating constraint needs to be selected.     -   f) Step 6 Determine a matrix of in parallel and in series         connections of the minimum quantity of LED dies (e.g. 40 LED         dies)     -   g) Step 7 Calculate the voltage and the total wattage required         to successfully drive the LED light to perform the maximum         lumens output.

The present disclosure of a two-level LED security light provides a unique lifestyle lighting solution. The motivation of creating such lifestyle lighting solution has less to do with the energy saving aspect of the low level illumination mode because LED is already a very energy saving light source compared with the conventional incandescent light source. For instance, a 10-watt LED security light when operated at a low level at 30% illumination it only saves 7 watts, which is not as significant as a 100-watt incandescent bulb which can save as much as 70 watts when operated at 30% illumination for a low level mode. While it is always good to save some extra energy, it is however not the main incentives for developing the present invention; the lifestyle lighting solution of the present disclosure is featured with two innovations which meaningfully improve the exquisite tastes of living in the evening, the first innovation is the creation of an aesthetic scene for the outdoor living environment, wherein at dusk the LED security light is automatically turned on by the photo sensor to perform the low level illumination which is necessary for creating a soft and aesthetic night scene for the outdoor living area (such soft and aesthetic night view is not achievable by the high level illumination however), the second innovation is the creation of a navigation capacity similar to a light house effect for guiding people to safely move toward a destination in the outdoor living area without getting lost or encountering an accident. These two innovative functions coupled with the motion sensor to increase illumination when people enter into the short detection area makes the present invention a perfect lifestyle lighting solution for enjoying an exquisite taste of evening life.

The above-mentioned descriptions represent merely the exemplary embodiment of the present disclosure, without any intention to limit the scope of the present disclosure thereto. Various equivalent changes, alternations or modifications based on the claims of present disclosure are all consequently viewed as being embraced by the scope of the present disclosure. 

What is claimed is:
 1. A two-level LED security light comprising: a light-emitting unit configured with at least a first LED load for emitting light with a low color temperature and at least a second LED load for emitting light with a high color temperature; a diffuser covering the first LED load and the second LED load to create a diffused light with a mingled light color temperature; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and an external control unit including at least a first external control device outputting at least one first external control signal; wherein the loading and power control unit comprises at least a first controller and a switching circuitry, wherein the switching circuitry is composed of a first controllable switching device and a second controllable switching device, wherein the first controller is electrically and respectively coupled with the light sensing control unit, the motion sensing unit, the first controllable switching device, the second controllable switching device, and the first external control device; wherein the switching circuitry is electrically coupled between a power source of the power supply unit and the light-emitting unit, wherein the power source is a DC power source configured in the power supply unit to output at least one DC power; wherein the first LED load and the second LED load are respectively connected in parallel paths and are respectively and electrically coupled to the first controllable switching device and the second controllable switching device of the switching circuitry; wherein the first controller outputs control signals to respectively control a first conduction rate of the first controllable switching device and a second conduction rate of the second controllable switching device to perform different illumination modes of the two-level LED security light characterized by different light intensities and different mingled light color temperatures according to signals respectively received from the light sensing control unit, the motion sensing unit and the first external control device; wherein when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit manages to deliver a low level electric power to the light-emitting unit to perform a low level illumination mode emitting light with a low light intensity and a first mingled light color temperature; wherein when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the loading and power control unit manages to switch off the light-emitting unit; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit manages to deliver a high level electric power to the light-emitting unit to perform a high level illumination mode emitting light with a high light intensity and a second mingled light color temperature for a predetermined time duration before switching back to the low level illumination mode; wherein the first external control device generates the at least one first external control signal for tuning and setting the first mingled light color temperature of the low level illumination mode or for tuning and setting the second mingled light color temperature of the high level illumination mode; wherein the LEDs of the first LED load and the LEDs of the second LED load are respectively designed with a configuration of in series and/or in parallel connections such that when incorporated with an adequate level setting of the DC power source an electric current passing through each LED of the first LED load and each LED of the second LED load remains at an adequate level such that a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring electrical characteristics of an LED, wherein V_(th) is a reference value of a threshold voltage required to trigger the LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across the LED to avoid a thermal damage or burning out of LED construction.
 2. The two-level LED security light according to claim 1, wherein the low color temperature is a color temperature value located in a range between 2000 K and 3000 K, wherein the high color temperature is a color temperature value located between 4000 K and 6500 K.
 3. The two-level LED security light according to claim 1, wherein the low light intensity is located in a range between 0% and 50% of a maximum light intensity designed for the two-level LED security light and the high light intensity is located in a range between 50% and 100% of the maximum light intensity designed for the two-level LED security light.
 4. The two-level LED security light according to claim 1, wherein when each of the first LED load and the second LED load is configured with a plurality of LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series, a working voltage across the first LED load or the second LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series.
 5. The two-level LED security light according to claim 4, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts, wherein the LED has the voltage V across each LED complying with an operating constraint of 2.5 volts<V<3.5 volts and the working voltages imposed on the first LED load and the second LED load respectively represented by V_(N) and V_(M) are confined in domains expressed by N×2.5 volts<V_(N)<N×3.5 volts and M×2.5 volts<V_(M)<M×3.5 volts, wherein N and M are positive integrals denoting respective numbers of series connected LEDs in the first LED load and the second LED load.
 6. The two-level LED security light according to claim 1, wherein the first controllable switching device comprises at least one first semiconductor switching device working in conjunction with the first controller to control the first conduction rate of the first controllable switching device; wherein the second controllable switching device comprises at least one second semiconductor switching device working in conjunction with the first controller to control the second conduction rate of the second controllable switching device.
 7. The two-level LED security light according to claim 1, wherein the first controllable switching device is a first LED driver outputting a first electric power delivered to the first LED load; wherein the second controllable switching device is a second LED driver outputting a second electric power to the second LED load.
 8. The two-level LED security light according to claim 1, wherein when the light-emitting unit is operated in the low level illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the first mingled light color temperature of the diffused light created thru the light diffuser; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates in response to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the switching circuitry to increase a first electric power delivered to the first LED load and at the same time to decrease a second electric power delivered to the second LED load such that a sum of the first electric power and the second electric power remains essentially unchanged; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the switching circuitry to decrease the first electric power delivered to the first LED load and at the same time to increase the second electric power delivered to the second LED load such that a sum of the first electric power and the second electric power remains essentially unchanged and is equal to the low level electric power in the low level illumination mode.
 9. The two-level LED security light according to claim 1, wherein when the light-emitting unit is operated in the high level illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the second mingled light color temperature of the diffused light created thru the light diffuser; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates in response to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the switching circuitry to increase a first electric power delivered to the first LED load and at the same time to decrease a second electric power delivered to the second LED load such that a sum of the first electric power and the second electric power remains essentially unchanged; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the switching circuitry to decrease the first electric power delivered to the first LED load and at the same time to increase the second electric power delivered to the second LED load such that the sum of the first electric power and the second electric power remains essentially unchanged and is equal to the high level electric power in the high level illumination mode.
 10. The two-level LED security light according to claim 1, wherein when the light-emitting unit is in a conduction state, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable, wherein the first controller in response to the at least one first external control signal received respectively outputs a first PWM signal to control the first conduction rate of the first controllable switching device and a second PWM signal to control the second conduction rate of the second controllable switching device with an arrangement that the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device are reversely adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load is maintained essentially at a constant level while the mingled light color temperature of the light emitted by the first LED load and the light emitted by the second LED load thru the light diffuser is proportionately adjusted according to the at least one first external control signal to perform a color temperature tuning of the first mingled light color temperature of the low level illumination or the second mingled light color temperature of the high level illumination.
 11. The two-level LED security light according to claim 10, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the at least one voltage signal with a voltage value is the at least one first external control signal, wherein upon receiving the at least one first external control signal the first controller operates to perform a corresponding mingled light color temperature according to the voltage value of the at least one voltage signal generated by the voltage divider.
 12. The two-level LED security light according to claim 1, wherein the first controller is programmed to operate with at least one color temperature switching scheme comprising a plurality of different mingled light color temperature tuning processes for tuning and selecting the first mingled light color temperature of the low level illumination mode or for tuning and selecting the second mingled light color temperature of the high level illumination mode, wherein paired combinations of the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device for respectively controlling a first electric power delivered to the first LED load and a second electric power delivered to the second LED load for creating different mingled light color temperatures are preprogrammed for operating a pick and play process according to the at least one first external control signal received and interpreted by the first controller for performing a selected mingled light color temperature; wherein in programming the paired combinations of different conduction rates of the switching circuitry, the first electric power delivered to the first LED load and the second electric power delivered to the second LED load are complementarily and reversely adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged.
 13. The two-level LED security light according to claim 12, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the first controller operates the pick and play process to activate a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme according to the voltage value of the at least one voltage signal outputted by the voltage divider.
 14. The two-level LED security light according to claim 13, wherein the voltage divider is designed with a step-less/free setting switch, wherein the voltage divider is configured to operate with a variable resistor to output a voltage value corresponding to a final parking location of a switching motion of the step-less/free setting switch on the variable resistor; wherein a full range of the voltage value outputted by the voltage divider corresponding to a full length of the variable resistor is divided into a plurality of different voltage domains for respectively activating the pick and play process, wherein the step-less/free setting switch is allowed to park at any location on the variable resistor to generate a corresponding voltage value to the first controller, wherein the first controller is designed to operate the pick and play process according to a belonging of a voltage domain with respect to the corresponding voltage value received from the voltage divider for selecting and activating a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme corresponding to the voltage domain.
 15. The two-level LED security light according to claim 12, wherein the first external control device includes a selection switch configured with a plurality of switching positions with each of the plurality of switching positions respectively for activating a corresponding process in the first controller, wherein when a switching position is operated by the selection switch, a corresponding mingled light color temperature switching process is activated to perform a corresponding mingled light color temperature.
 16. The two-level LED security light according to claim 15, wherein the selection switch is a slide switch, a rotary switch, a pull chain switch or any switch design having a capacity to perform the same selection function.
 17. The two-level LED security light according to claim 12, wherein the first external control device includes at least one push button or one touch pad and the at least one external control signal is a voltage signal generated by operating the push button or the touch pad, wherein upon receiving the voltage signal the first controller operates the pick and play process to alternately perform the selected mingled light color temperature in the at least one color temperature switching scheme according to a preset sequence.
 18. The two-level LED security light according to claim 12, wherein the first external control device includes at least one wireless signal receiver to receive a wireless external control signal from a mobile device, a smart phone or a smart speaker for activating the pick and play process for selecting a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme for performing a corresponding first mingled light color temperature or a corresponding second mingled light color temperature.
 19. The two-level LED security light according to claim 12, wherein the first external control device is a power interruption detection circuitry electrically coupled to the first controller for detecting a short power interruption signal; wherein when the short power interruption signal is detected, the first controller operates to alternately switch a selection of different mingled light color temperatures according to the at least one color temperature switching scheme preprogrammed.
 20. The two-level LED security light according to claim 1, wherein each of the first controllable switching device and the second controllable switching device comprises at least one uni-directional semiconductor switching element, wherein the uni-directional switching elements are bipolar junction transistors (BJTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).
 21. A lifestyle LED security light comprising: a light-emitting unit, configured with at least a first LED load for emitting light with a low color temperature and at least a second LED load for emitting light with a high color temperature; a diffuser covering the first LED load and the second LED load to create a diffused light with a mingled light color temperature; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and an external control unit including at least a first external control device outputting at least one first external control signal; wherein the loading and power control unit comprises at least a first controller and a switching circuitry, wherein the first controller is electrically and respectively coupled with the light sensing control unit, the motion sensing unit, the switching circuitry and the first external control device; wherein the switching circuitry is electrically coupled between a power source of the power supply unit and the light-emitting unit, wherein the power source is a DC power source configured in the power supply unit to output at least one DC power; wherein the switching circuitry comprises at least a first controllable switching device and at least a second controllable switching device; wherein the first LED load and the second LED load are respectively connected in parallel paths and are further respectively and electrically coupled to the first controllable switching device and the second controllable switching device; wherein the first controller outputs a first control signal to control a first conduction rate of the first controllable switching device for delivering a first electric power to the first LED load and simultaneously a second control signal to control a second conduction rate of the second controllable switching device for delivering a second electric power to the second LED load such that the light-emitting unit respectively generates illuminations of different light intensities and different mingled light color temperatures for performing different illumination modes according to signals respectively received from the light sensing control unit, the motion sensing unit and the first external control device; wherein when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit manages to deliver an electric power to the light-emitting unit to perform a first illumination mode with a first level illumination characterized by a first light intensity and a first mingled light color temperature for a first predetermined time duration with the motion sensing unit being temporarily deactivated; wherein upon a maturity of the first predetermined time duration the loading and power control unit manages to cutoff the electric power delivered to the light-emitting unit and at the same time the motion sensing unit is activated; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit manages to deliver the electric power to the light-emitting unit to perform a second illumination mode with a second level illumination characterized by a second light intensity and a second mingled light color temperature for a second predetermined time duration before being switched back to a turned off state; wherein the second light intensity of the second level illumination is equal to or higher than the first light intensity of the first level illumination; wherein when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the loading and power control unit manages to switch off the light-emitting unit; wherein the first external control device generates the at least one first external control signal for tuning and setting the first mingled light color temperature of the first illumination mode or for tuning and setting the second mingled light color temperature of the second illumination mode; wherein the LEDs of the first LED load and the LEDs of the second LED load are respectively designed with a configuration of in series and/or in parallel connections such that when incorporated with an adequate level setting of the DC power source of the power supply unit an electric current passing through each LED of the first LED load and each LED of the second LED load remains at an adequate level such that a voltage V across each LED chip complies with an operating constraint of V_(th)<V<V_(max) featuring electrical characteristics of the LED chip, wherein V_(th) is a reference value of a threshold voltage required to trigger the LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across the LED to avoid a thermal damage or burning out of LED construction.
 22. The lifestyle LED security light according to claim 21, wherein a value of the low color temperature is located in a range between 2000 K and 3000 K, wherein a value of the high color temperature is located between 4000 K and 6500 K.
 23. The lifestyle LED security light according to claim 21, wherein when each of the first LED load and the second LED load is configured with a plurality of LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series, a working voltage across the first LED load or the second LED load is confined in a domain between a minimum voltage equal to a sum of the threshold voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series.
 24. The lifestyle LED security light according to claim 23, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts, wherein the LED has the voltage V across each LED complying with an operating constraint of 2.5 volts<V<3.5 volts and the working voltages imposed on the first LED load and the second LED load respectively represented by V_(N) and V_(M) are confined in domains expressed by N×2.5 volts<V_(N)<N×3.5 volts and M×2.5 volts<V_(M)<M×3.5 volts, wherein N and M are positive integrals denoting respective numbers of series connected LEDs in the first LED load and in the second LED load.
 25. The lifestyle LED security light according to claim 21, wherein the first controllable switching device comprises at least one first semiconductor switching device working in conjunction with the first controller to control the first conduction rate of the first controllable switching device; wherein the second controllable switching device comprises at least one second semiconductor switching device working in conjunction with the first controller to control the second conduction rate of the second controllable switching device.
 26. The lifestyle LED security light according to claim 21, wherein the first controllable switching device is a first LED driver outputting the first electric power delivered to the first LED load; wherein the second controllable switching device is a second LED driver outputting the second electric power delivered to the second LED load.
 27. The lifestyle LED security light according to claim 21, wherein the first mingled light color temperature of the first level illumination in performing the first illumination mode is the low color temperature, wherein the second controllable switching device is in a cutoff state and the first controller outputs only the first control signal to control the first conduction rate of the first controllable switching device to deliver the electric power to the light-emitting unit to determine the light intensity of the first illumination mode.
 28. The lifestyle LED security light according to claim 21, wherein the second mingled light color temperature of the second level illumination in performing the second illumination mode is the high color temperature, wherein the first controllable switching device is in a cutoff state and the first controller outputs only the second control signal to control the second conduction rate of the second controllable switching device to deliver the electric power to the light-emitting unit to determine the light intensity of the second illumination mode.
 29. The lifestyle LED security light according to claim 21, wherein when the light-emitting unit is in the first illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the mingled light color temperature of the diffused light created thru the light diffuser; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the external control signal operates to control the first controllable switching device to increase the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally decrease the second electric power delivered to the second LED load; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the external control signal operates to control the first controllable switching device to decrease the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally increase the second electric power delivered to the second LED load.
 30. The lifestyle LED security light according to claim 21, wherein when the light-emitting unit is in the second illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the mingled light color temperature of the diffused light created thru the light diffuser; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the first controllable switching device to increase the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally decrease the second electric power delivered to the second LED load; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the at least one first external control signal operates to control the first controllable switching device to decrease the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally increase the second electric power delivered to the second LED load.
 31. The lifestyle LED security light according to claim 21, wherein when the light-emitting unit is in a conduction state, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable, wherein the first controller in response to the at least one first external control signal received respectively outputs a first PWM signal to control the first conduction rate of the first controllable switching device and a second PWM signal to control the second conduction rate of the second controllable switching device with an arrangement that the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device are reversely adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load is maintained essentially at a constant level while the mingled light color temperature of the light emitted by the first LED load and the light emitted by the second LED load thru the light diffuser is proportionately adjusted according to the at least one first external control signal to perform a color temperature tuning of the first mingled light color temperature of the low level illumination or the second mingled light color temperature of the high level illumination.
 32. The lifestyle LED security light according to claim 31, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the at least one voltage signal with a voltage value is the at least one first external control signal, wherein upon receiving the at least one first external control signal the first controller operates to perform a corresponding mingled light color temperature according to the voltage value of the at least one voltage signal generated by the voltage divider.
 33. The lifestyle LED security light according to claim 21, wherein the first controller is programmed to operate with at least one color temperature switching scheme comprising a plurality of different mingled light color temperature tuning processes for tuning and selecting the first mingled light color temperature of the first illumination mode or for tuning and setting the second mingled light color temperature of the second illumination mode, wherein paired combinations of the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device for respectively controlling the first electric power delivered to the first LED load and the second electric power delivered to the second LED load for creating different mingled light color temperatures are preprogrammed for operating a pick and play process according to the at least one first external control signal received and interpreted by the first controller for performing a selected mingled light color temperature; wherein in programming the paired combinations of different conduction rates of the switching circuitry, the first electric power delivered to the first LED load and the second electric power delivered to the second LED load are complementarily and reversely adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged.
 34. The lifestyle LED security light according to claim 33, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein upon receiving the at least one first external control signal the first controller operates the pick and play process to activate a corresponding mingled light color temperature process in the at least one color temperature switching scheme according to the voltage value of the at least one voltage signal outputted by the voltage divider.
 35. The lifestyle LED security light according to claim 34, wherein the voltage divider is designed with a step-less/free setting switch, wherein the voltage divider is configured to operate with a variable resistor to output a voltage value corresponding to a final parking location of a switching motion of the step-less/free setting switch on the variable resistor; wherein a full range of the voltage value outputted by the voltage divider corresponding to a full length of the variable resistor is divided into a plurality of different voltage domains for respectively activating the pick and play process, wherein the step-less/free setting switch is allowed to park at any location on the variable resistor to generate a corresponding voltage value to the first controller, wherein the first controller is designed to operate the pick and play process according to a belonging of a voltage domain with respect to the corresponding voltage value received from the voltage divider for selecting and activating a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme corresponding to the voltage domain.
 36. The lifestyle LED security light according to claim 33, wherein the first external control device includes at least one push button or one touch pad and the at least one external control signal is a voltage signal generated by operating the push button or the touch pad, wherein upon receiving the voltage signal the first controller operates the pick and play process to alternately perform the selected mingled light color temperature in the at least one color temperature switching scheme according to a preset sequence.
 37. The lifestyle LED security light according to claim 33, wherein the first external control device includes a selection switch configured with a plurality of switching positions with each of the plurality of switching positions respectively for activating a corresponding process in the first controller, wherein when a switching position is operated by the selection switch, a corresponding mingled light color temperature switching process is activated to perform a corresponding mingled light color temperature.
 38. The lifestyle LED security light according to claim 37, wherein the selection switch is a slide switch, a rotary switch, a pull chain switch or any switch design having a capacity to perform the same selection function.
 39. The lifestyle LED security light according to claim 33, wherein the first external control device includes a power interruption detection circuitry electrically coupled to the first controller for detecting a short power interruption signal; wherein when the short power interruption signal is detected, the first controller operates to alternately switch a selection of different mingled light color temperatures according to the at least one color temperature switching scheme preprogrammed.
 40. The lifestyle LED security light according to claim 33, wherein the first external control device includes at least one wireless signal receiver to receive a wireless external control signal from a mobile device, a smart phone or a smart speaker and to convert the wireless external control signal into a message carrying sensing signal interpretable and executable by the first controller for activating the pick and play process for selecting a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme for performing a corresponding first mingled light color temperature or a corresponding second mingled light color temperature.
 41. The lifestyle LED security light according to claim 21, wherein each of the first controllable switching device and the second controllable switching device comprises at least one uni-directional semiconductor switching element, wherein the uni-directional switching elements are bipolar junction transistors (BJTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).
 42. A lifestyle LED security light comprising: a light-emitting unit, configured with at least a first LED load for emitting light with a low color temperature and at least a second LED load for emitting light with a high color temperature; a diffuser covering the first LED load and the second LED load to create a diffused light with a mingled light color temperature; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and an external control unit including at least a first external control device outputting at least one first external control signal; wherein the loading and power control unit comprises at least a first controller and a switching circuitry, wherein the first controller is electrically and respectively coupled with the light sensing control unit, the motion sensing unit, the switching circuitry and the first external control device; wherein the switching circuitry is electrically coupled between at least one power source of the power supply unit and the light-emitting unit, wherein the at least one power source is a DC power source configured in the power supply unit to output at least one DC power; wherein the switching circuitry comprises at least a first controllable switching device and a second controllable switching device; wherein the first LED load and the second LED load are respectively connected in parallel paths and are further respectively and electrically coupled to the first controllable switching device and the second controllable switching device; wherein the first controller outputs a first control signal to control a first conduction rate of the first controllable switching device for delivering a first electric power to the first LED load and simultaneously the first controller also outputs a second control signal to control a second conduction rate of the second controllable switching device for delivering a second electric power to the second LED load such that the light-emitting unit respectively generates illuminations of different light intensities and different mingled light color temperatures for performing different illumination modes according to signals respectively received from the light sensing control unit, the motion sensing unit and the first external control device; wherein when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit manages to deliver an electric power to the light-emitting unit to perform a first illumination mode with a first level illumination characterized by a first light intensity and a first mingled light color temperature for a first predetermined time duration with the motion sensing unit being temporarily deactivated; wherein upon a maturity of the first predetermined time duration the loading and power control unit manages to reduce the electric power delivered to the light-emitting unit to generate a low level illumination characterized by a low light intensity and at the same time the motion sensing unit is activated; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit manages to increase the electric power delivered to light-emitting unit to perform a second illumination mode with a second level illumination characterized by a second light intensity and a second mingled light color temperature for a second predetermined time duration before being switched back to the low level illumination, wherein the second light intensity of the second level illumination is equal to or higher than the first light intensity of the first level illumination, wherein the first light intensity of the first level illumination is equal to or higher than the low light intensity of the low level illumination; wherein when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the loading and power control unit manages to switch off the light-emitting unit; wherein the first external control device generates the at least one first external control signal for tuning the first mingled light color temperature of the first illumination mode or for tuning the second mingled light color temperature of the second illumination mode; wherein the LEDs of the first LED load and the LEDs of the second LED load are respectively designed with a configuration of in series and/or in parallel connections such that when incorporated with an adequate level setting of the DC power source of the power supply unit an electric current passing through each LED of the first LED load and each LED of the second LED load remains at an adequate level such that a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring electrical characteristics of a LED, wherein V_(th) is a reference value of a threshold voltage required to trigger the LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across the LED to avoid a thermal damage or burning out of LED construction.
 43. The lifestyle LED security light according to claim 42, wherein the low color temperature is a color temperature value located in a range between 2000 K and 3000 K, wherein the high color temperature is a color temperature value located between 4000 K and 6500 K.
 44. The lifestyle LED security light according to claim 42, wherein when each of the first LED load and the second LED load is configured with a plurality of LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series, a working voltage across the first LED load or the second LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series.
 45. The lifestyle LED security light according to claim 44, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts, wherein the LED has the voltage V across each LED complying with an operating constraint of 2.5 volts<V<3.5 volts and the working voltages imposed on the first LED load and the second LED load respectively represented by V_(N) and V_(M) are confined in domains expressed by N×2.5 volts<V_(N)<N×3.5 volts and M×2.5 volts<V_(M)<M×3.5 volts, wherein N and M are positive integrals denoting respective numbers of series connected LEDs in the first LED load and the second LED load.
 46. The lifestyle LED security light according to claim 42, wherein the first controllable switching device comprises at least one first semiconductor switching device working in conjunction with the first controller to control the first conduction rate of the first controllable switching device; wherein the second controllable switching device comprises at least one second semiconductor switching device working in conjunction with the first controller to control the second conduction rate of the second controllable switching device.
 47. The lifestyle LED security light according to claim 42, wherein the first controllable switching device is a first LED driver outputting the first electric power delivered to the first LED load; wherein the second controllable switching device is a second LED driver outputting the second electric power to the second LED load.
 48. The lifestyle LED security light according to claim 42, wherein the first mingled light color temperature in performing the first illumination mode is the low color temperature, wherein the second controllable switching device is in a cutoff state and the first controller outputs only the first control signal to control the first conduction rate of the first controllable switching device to deliver the electric power to the light-emitting unit to determine the light intensity and the first mingled light color temperature of the first illumination mode.
 49. The lifestyle LED security light according to claim 42, wherein the second mingled light color temperature in performing the second illumination mode is the high color temperature, wherein the first controllable switching device is in a cutoff state and the first controller outputs only the second control signal to control the second conduction rate of the second controllable switching device to deliver the electric power to the light-emitting unit to determine the light intensity and the second mingled light color temperature of the second illumination mode.
 50. The lifestyle LED security light according to claim 42, wherein when the light-emitting unit is in a conduction state, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable, wherein the first controller in response to the at least one first external control signal received respectively outputs a first PWM signal to control the first conduction rate of the first controllable switching device and a second PWM signal to control the second conduction rate of the second controllable switching device with an arrangement that the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device are reversely adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load is maintained essentially at a constant level while the mingled light color temperature of the light emitted by the first LED load and the light emitted by the second LED load thru the light diffuser is proportionately adjusted according to the at least one first external control signal to perform a color temperature tuning of the first mingled light color temperature of the low level illumination or the second mingled light color temperature of the high level illumination.
 51. The lifestyle LED security light according to claim 50, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the at least one voltage signal with a voltage value is the at least one first external control signal, wherein upon receiving the at least one first external control signal the first controller operates to perform a corresponding mingled light color temperature according to the voltage value of the at least one voltage signal generated by the voltage divider.
 52. The lifestyle LED security light according to claim 42, wherein when the light-emitting unit is in the first illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the first mingled light color temperature; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the at least one first external control signal from the first external control device operates to control the first controllable switching device to increase the first electric power delivered to the first LED load and at the same time proportionally decrease the second electric power delivered to the second LED load; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the at least one first external control signal from the first external control device operates to control the first controllable switching device to decrease the first electric power delivered to the first LED load and at the same time proportionally increase the second electric power delivered to the second LED load.
 53. The lifestyle LED security light according to claim 42, wherein when the light-emitting unit is in the second illumination mode, a light intensity of the first LED load and a light intensity of the second LED load are respectively adjustable to tune the second mingled light color temperature; wherein upon receiving the at least one first external control signal from the first external control device the first controller operates to reversely and complementarily adjust the light intensity of the first LED load and the light intensity of the second LED load with the same pace such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged; wherein for tuning to a lower mingled light color temperature, the first controller upon receiving the at least one first external control signal from the first external control device operates to control the first controllable switching device to increase the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally decrease the second electric power delivered to the second LED load; wherein for tuning to a higher mingled light color temperature, the first controller upon receiving the at least one first external control signal from the first external control device operates to control the first controllable switching device to decrease the first electric power delivered to the first LED load and at the same time operates to control the second controllable switching device to proportionally increase the second electric power delivered to the second LED load.
 54. The lifestyle LED security light according to claim 42, wherein the first controller is programmed to operate with at least one color temperature switching scheme comprising a plurality of different mingled light color temperature tuning processes for tuning and selecting the first mingled light color temperature of the first illumination mode or for tuning and setting the second mingled light color temperature of the second illumination mode, wherein paired combinations of the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device for respectively controlling the first electric power delivered to the first LED load and the second electric power delivered to second LED load for creating different mingled light color temperatures are preprogrammed for operating a pick and play process according to the at least one first external control signal received and interpreted by the first controller for performing a selected mingled light color temperature; wherein in programming the paired combinations of different conduction rates of the switching circuitry, the first electric power delivered to the first LED load and the second electric power delivered to the second LED load are complementarily and reversely adjusted such that a total of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains essentially unchanged.
 55. The lifestyle LED security light according to claim 54, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least a voltage signal with a voltage value, wherein the first controller operates the pick and play process to activate a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme according to the voltage value of the at least one voltage signal outputted by the voltage divider.
 56. The lifestyle LED security light according to claim 55, wherein the voltage divider is designed with a step-less/free setting switch, wherein the voltage divider is configured to operate with a variable resistor to output a voltage value corresponding to a final parking location of a switching motion of the step-less/free setting switch on the variable resistor; wherein a full range of the voltage value outputted by the voltage divider corresponding to a full length of the variable resistor is divided into a plurality of different voltage domains for respectively activating the pick and play process, wherein the step-less/free setting switch is allowed to park at any location on the variable resistor to generate a corresponding voltage value to the first controller, wherein the first controller is designed to operate the pick and play process according to a belonging of a voltage domain with respect to the corresponding voltage value received from the voltage divider for selecting and activating a corresponding mingled light color temperature process in the at least one color temperature switching scheme corresponding to the voltage domain.
 57. The lifestyle LED security light according to claim 54, wherein the first external control device includes a push button or a touch pad and the at least one first external control signal is a voltage signal generated by operating the push button or the touch pad, wherein upon receiving the voltage signal the first controller operates the pick and play process to alternately perform the selected mingled light color temperature in the at least one color temperature switching scheme according to a preset sequence.
 58. The lifestyle LED security light according to claim 54, wherein the first external control device includes a selection switch configured with a plurality of switching positions with each of the plurality of switching positions respectively for activating a corresponding process in the first controller, wherein when a switching position is operated by the selection switch, a corresponding mingled light color temperature switching process is activated to perform a corresponding mingled light color temperature.
 59. The lifestyle LED security light according to claim 58, wherein the selection switch is a slide switch, a rotary switch, a pull chain switch or any switch design having a capacity to perform the same selection function.
 60. The lifestyle LED security light according to claim 54, wherein the first external control device includes a power interruption detection circuitry electrically coupled to the first controller for detecting a short power interruption signal; wherein when the short power interruption signal is detected, the first controller operates to alternately switch a selection of different mingled light color temperatures according to the at least one color temperature switching scheme preprogrammed.
 61. The lifestyle LED security light according to claim 54, wherein the first external control device includes a wireless signal receiver to receive a wireless external control signal from a mobile device, a smart phone or a smart speaker and to convert the wireless external control signal into the at least one first external control signal interpretable and executable by the first controller for activating the pick and play process for selecting a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme for performing a corresponding first mingled light color temperature or a corresponding second mingled light color temperature.
 62. The lifestyle LED security light according to claim 42 wherein each of the first controllable switching device and the second controllable switching device comprises at least one uni-directional semiconductor switching element, wherein the uni-directional switching elements are bipolar junction transistors (BJTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).
 63. A two-level LED security light comprising: a light-emitting unit configured with an LED load; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and an external control unit including at least a first external control device outputting at least one first external control signal; wherein the LED load of the light-emitting unit includes a plurality of LEDs divided into two sets with a first set of N number LEDs and a second set of M number LEDs electrically and respectively connected in parallel paths, wherein N and M are positive integers, wherein the N number LEDs emits light with a low color temperature and the M number LEDs emits light with a high color temperature, wherein the first set of N number LEDs and the second set of M number LEDs are covered by a diffuser to create a diffused light with a mingled light color temperature; wherein the loading and power control unit includes at least a first controller and a switching circuitry, wherein the switching circuitry is electrically coupled between a DC power source configured in the power supply unit and the light-emitting unit, wherein the switching circuitry comprises a first controllable switching device electrically coupled between the DC power source and the first set of N number LEDs and a second controllable switching device electrically coupled between the DC power source and the second set of M number LEDs; wherein the first controller is electrically coupled with the light sensing control unit, the motion sensing unit, the first controllable switching device, the second controllable switching device and at least the first external control device; wherein the first controller outputs a first control signal to control a first conduction rate of the first controllable switching device for delivering a first electric power to the first set of N number LEDs and simultaneously the first controller also outputs a second control signal to control a second conduction rate of the second controllable switching device for delivering a second electric power to the second set of M number LEDs such that the light-emitting unit respectively generates illuminations of different light intensities and different mingled light color temperatures for performing different illuminations according to signals respectively received from the light sensing control unit, the motion sensing unit and at least the first external control device; wherein when an ambient light detected by the light sensing control unit is lower than a predetermined value, the loading and power control unit manages to deliver a low level electric power to the light-emitting unit to generate a low level illumination characterized by a low light intensity and a first mingled light color temperature; wherein when the ambient light detected by the light sensing control unit is higher than the predetermined value, the loading and power control unit manages to switch off the light-emitting unit; wherein when a motion intrusion is detected by the motion sensing unit, the loading and power control unit manages to deliver a high level electric power to the light-emitting unit to generate a high level illumination characterized by a high light intensity and a second mingled light color temperature for a predetermined time duration before switching back to perform the low level illumination with the first mingled light color temperature; wherein the first external control device generates the at least one first external control signal for tuning the first mingled light color temperature of the low level illumination or for tuning the second mingled light color temperature of the high level illumination; wherein the plurality of LEDs of the first set of N number LEDs and the second set of M number LEDs in conjunction with a power level setting of the DC power source of the power supply unit are respectively designed with a configuration of in series and/or in parallel connections of LEDs such that an electric current passing through each LED of the light-emitting unit remains at an adequate level, and a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring electrical characteristics of an LED; wherein V_(th) is a reference value of a threshold voltage required to trigger each LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across each LED to avoid a thermal damage or burning out of LED construction.
 64. The two-level LED security light according to claim 63, wherein the low color temperature is a color temperature value located in a range between 2000 K and 3000 K, wherein the high color temperature is a color temperature value located between 4000 K and 6500 K.
 65. The two-level LED security light according to claim 63, wherein the low light intensity is located in a range between 0% and 50% of a maximum light intensity designed for the two-level LED security light and the high light intensity is located in a range between 50% and 100% of the maximum light intensity designed for the two-level LED security light.
 66. The two-level LED security light according to claim 63, wherein a total wattage of the M number LEDs is greater than a total wattage of the N number LEDs.
 67. The two-level LED security light according to claim 63, wherein a total wattage of the M number LEDs is equal to a total wattage of the N number LEDs.
 68. The two-level LED security light according to claim 63, wherein the first controllable switching device comprises at least one first semiconductor switching device working in conjunction with the first controller to control the first conduction rate of the first controllable switching device; wherein the second controllable switching device comprises at least one second semiconductor switching device working in conjunction with the first controller to control the second conduction rate of the second controllable switching device.
 69. The two-level LED security light according to claim 63, wherein the first controllable switching device is a first LED driver outputting the first electric power delivered to the first LED load; wherein the second controllable switching device is a second LED driver outputting the second electric power to the second LED load.
 70. The two-level LED security light according to claim 63, wherein when the two-level LED security light is operated to generate the low level illumination, the first mingled light color temperature is adjustable by the first controller, wherein the first controller in response to the at least one first external control signal outputs PWM signals to respectively control time lengths of conduction periods of the first controllable switching device and the second controllable switching device to vary in a reverse manner such that a light intensity of the first set of N number LEDs with the low color temperature and a light intensity of the second set of M number LEDs with the high color temperature are reversely adjusted with the same pace to produce a variable mingled light color temperature thru the light diffuser for performing a color temperature tuning of the low level illumination.
 71. The two-level LED security light according to claim 63, wherein when the two-level LED security light is operated to generate the high level illumination, the second mingled light color temperature of the high level illumination is further adjustable by the first controller, wherein the first controller in response to the at least one first external control signal outputs PWM signals to respectively control time lengths of conduction periods of the first controllable switching device and the second controllable switching device to vary in a reverse manner such that a light intensity of the first set of N number LEDs with the low color temperature and a light intensity of the second set of M number LEDs with the high color temperature are reversely adjusted with the same pace to produce a variable mingled light color temperature thru the light diffuser for performing a color temperature tuning of the high level illumination.
 72. The two-level LED security light according to claim 63, wherein when the light-emitting unit is in a conduction state, a light intensity of the N number LEDs and a light intensity of the M number LEDs are respectively adjustable, wherein the first controller in response to the at least one first external control signal received respectively outputs a first PWM signal to control the first conduction rate of the first controllable switching device and a second PWM signal to control the second conduction rate of the second controllable switching device with an arrangement that the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device are reversely adjusted such that a sum of the first electric power delivered to the N number LEDs and the second electric power delivered to the M number LEDs is maintained essentially at a constant level while the mingled light color temperature of the light emitted by the N number LEDs and the light emitted by the M number LEDs thru the light diffuser is proportionately adjusted according to the at least one first external control signal to perform a color temperature tuning of the first mingled light color temperature of the low level illumination or the second mingled light color temperature of the high level illumination.
 73. The two-level LED security light according to claim 72, wherein the first external control device includes a voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the at lead one voltage signal with a voltage value is the at least one first external control signal, wherein upon receiving the at least one first external control signal the first controller operates to perform a corresponding mingled light color temperature according to the voltage value of the at least one voltage signal generated by the voltage divider.
 74. The two-level LED security light according to claim 63 wherein the first controller is programmed to operate with at least one color temperature switching scheme comprising a plurality of different mingled light color temperature tuning processes for tuning and selecting the first mingled light color temperature of the low level illumination or for tuning the second mingled light color temperature of the high level illumination, wherein paired combinations of a first conduction rate of the first controllable switching device and a second conduction rate of the second controllable switching device for respectively controlling a first electric power delivered to the first set of N number LEDs and a second electric power delivered to the second set of M number LEDs for creating different mingled light color temperatures are preprogrammed for operating a pick and play process according to the at least one first external control signal executable and interpretable by the first controller for performing a selected mingled light color temperature; wherein in programming the paired combinations of different conduction rates of the switching circuitry, the first electric power delivered to the first set of N number LEDs and the second electric power delivered to the second set of M number LEDs are complementarily and reversely adjusted such that a sum of the first electric power delivered to the first set of N number LEDs and the second electric power delivered to the second set of M number LEDs remains essentially unchanged.
 75. The two-level LED security light according to claim 74, wherein the first external control device includes voltage divider, wherein the voltage divider is configured to output at least one voltage signal with a voltage value, wherein the first controller operates the pick and play process to activate a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme according to the voltage value of the at least one voltage signal outputted by the voltage divider.
 76. The two-level LED security light according to claim 75, wherein the voltage divider is designed with a step-less/free setting switch, wherein the voltage divider is configured to operate with a variable resistor to output an analog signal with a voltage value corresponding to a final parking location of a switching motion of the step-less/free setting switch on the variable resistor; wherein a second controller is electrically coupled between the first external control device and the first controller, wherein the second controller comprises a detection device to convert the analog signal into a digital signal interpretable and executable by the first controller, wherein a full range of the voltage value outputted by the voltage divider corresponding to a full length of the variable resistor is divided into a plurality of different digital voltage domains respectively represented by a digital value for respectively activating the pick and play process, wherein the step-less/free setting switch is allowed to park at any location on the variable resistor to generate a corresponding voltage value of the at least one first external control signal to the second controller, wherein the second controller operates to output a digital signal to the first controller according to a belonging of a voltage domain with respect to the corresponding voltage value received from the voltage divider.
 77. The two-level LED security light according to claim 75, wherein the voltage divider is designed with a step-less/free setting switch, wherein the voltage divider is configured to operate with a variable resistor to output an analog signal with a voltage value corresponding to a final parking location of a switching motion of the step-less/free setting switch on the variable resistor; wherein the first controller is further designed to convert the analog signal from the voltage divider into an executable digital signal for activating the pick and play process, wherein a full range of the voltage value outputted by the voltage divider corresponding to a full length of the variable resistor is divided into a plurality of different digital voltage domains respectively represented by a digital value for respectively activating the pick and play process, wherein the step-less/free setting switch is allowed to park at any location on the variable resistor to generate a corresponding voltage value, wherein the corresponding voltage value is converted into a corresponding digital signal according to a belonging of a voltage domain with respect to the corresponding voltage value received from the voltage divider.
 78. The two-level LED security light according to claim 74, wherein the first external control device includes a selection switch configured with a plurality of switching positions with each of the plurality of switching positions respectively for activating a corresponding process in the first controller, wherein when a switching position is operated by the selection switch, a corresponding mingled light color temperature switching process is activated to perform a corresponding mingled light color temperature.
 79. The two-level LED security light according to claim 78, wherein the selection switch is a slide switch, a rotary switch, a pull chain switch or any switch design having a capacity to perform the same selection function.
 80. The two-level LED security light according to claim 74, wherein the first external control device includes at least one push button or one touch pad and the at least one external control signal is a voltage signal generated by operating the push button or the touch pad, wherein upon receiving the voltage signal the first controller operates the pick and play process to alternately perform the selected mingled light color temperature in the at least one color temperature switching scheme according to a preset sequence.
 81. The two-level LED security light according to claim 74, wherein the first external control device is a power interruption detection circuitry electrically coupled to the first controller for detecting a short power interruption signal; wherein when the short power interruption signal is detected, the first controller operates to alternately switch a selection of different mingled light color temperatures according to the at least one color temperature switching scheme preprogrammed.
 82. The two-level LED security light according to claim 74, wherein the first external control device includes a wireless signal receiver to receive a wireless external control signal from a mobile device, a smart phone or a smart speaker and to convert the wireless external control signal into the at least one first external control signal interpretable and executable by the first controller for activating the pick and play process for selecting a corresponding mingled light color temperature tuning process in the at least one color temperature switching scheme for performing a corresponding first mingled light color temperature performance or a corresponding second mingled light color temperature performance.
 83. The two-level LED security light according to claim 63, wherein when each of the first set of N number LEDs and the second set of M number LEDs is configured with a plurality of LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series, a working voltage across each of the first set of N number LEDs and the second set of the M number LEDs is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs electrically connected in series or sets of in parallel connected LEDs electrically connected in series.
 84. The two-level LED security light according to claim 83, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts, wherein when the LED has the voltage V across each LED complying with an operating constraint of 2.5 volts<V<3.5 volts and the first set of N number LEDs and the second set of M number LEDs are required to operate with respective working voltages V_(N) and V_(M) confined in domains expressed by N_(s)×2.5 volts<V_(N)<N_(s)×3.5 volts and M_(s)×2.5 volts<V_(M)<M_(s)×3.5 volts, with N_(s) and M_(s) respectively denoting the numbers of series connected LEDs in the first set of N number LEDs and the second set of M number LEDs, wherein N_(s)≤N and M_(s)≤M.
 85. The two-level LED security light according to claim 63, wherein each of the first controllable switching device and the second controllable switching device comprises at least one uni-directional semiconductor switching element, wherein the uni-directional switching elements are bipolar junction transistors (BJTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).
 86. An LED lighting device configured with a running mingled light color temperature switching process of a color temperature switching scheme, comprising: a light-emitting unit configured with at least a first LED load for emitting light with a low color temperature and at least a second LED load for emitting light with a high color temperature; a diffuser covering the first LED load and the second LED load to create a diffused light with a mingled light color temperature; a mingled light color temperature tuning algorithm to generate the color temperature switching scheme comprising a plurality of different mingled light color temperature performances and to operate a running pick and play process of the plurality of different mingled light color temperature performances in the color temperature switching scheme by turns according to a prearranged sequence; a loading and power control unit to execute each of the plurality of different mingled light color temperature performances by turns according to the prearranged sequence to implement the running mingled light color temperature switching process; a power supply unit; and at least a first external control device to output at least one first external control signal to activate the running mingled light color temperature switching process; wherein the loading and power control unit comprises at least a first controller and a switching circuitry, wherein the switching circuitry is composed of a first controllable switching device and a second controllable switching device, wherein the first controller is electrically and respectively coupled with the first controllable switching device, the second controllable switching device, and the first external control device; wherein the switching circuitry is electrically coupled between a power source of the power supply unit and the light-emitting unit, wherein the power source is a DC power source configured in the power supply unit to output at least one DC power; wherein the first LED load and the second LED load are connected in parallel and are respectively and electrically coupled to the first controllable switching device and the second controllable switching device of the switching circuitry; wherein the first controller outputs a first control signal to control a first conduction rate of the first controllable switching device and a second control signal to control a second conduction rate of the second controllable switching device to respectively deliver a first electric power to the first LED load and a second electric power to the second LED load to perform an illumination with a light intensity and a mingled light color temperature performance according to the at least one first external control signal received from at least the first external control device; wherein the first controller is designed with the color temperature switching scheme comprising the plurality of different mingled light color temperature performances selectable for performing the mingled light color temperature of the light-emitting unit; wherein each of the plurality of different diffused light color temperature performances is designed according to the mingled light color temperature tuning algorithm that the first conduction rate of the first controllable switching device and the second conduction rate of the second controllable switching device are reversely and complementarily adjusted such that a sum of the first electric power delivered to the first LED load and the second electric power delivered to the second LED load remains unchanged while the mingled light color temperature is changed to a lower color temperature performance or a higher color temperature performance; wherein upon receiving the at least one first external control signal from the first external control device, the first controller operates a running pick and play process to continuously and recurrently perform each of the plurality of different mingled light color temperature performances by turns according to the prearranged sequence to implement the running mingled light color temperature switching process, the running mingled light color temperature switching process ceases at a time when the at least one first external control signal is terminated or a second external control signal is received by the first controller.
 87. The LED lighting device configured with a running mingled light color temperature switching process of a color temperature switching scheme according to claim 86, wherein the low color temperature is a color temperature value located in a range between 2000 K and 3000 K, wherein the high color temperature is a color temperature value located between 4000 K and 6500 K.
 88. The LED lighting device configured with a running mingled light color temperature switching process of a color temperature switching scheme according to claim 86, wherein the first external control device is a power detection device, wherein when a power on is detected, the first controller operates to activate the running mingled light color temperature switching process.
 89. The LED lighting device configured with a running mingled light color temperature switching process of a color temperature switching scheme according to claim 86, wherein the first external control device is a selection switch to activate or deactivate the running mingled light color temperature switching process.
 90. The LED lighting device configured with a running mingled light color temperature switching process of a color temperature switching scheme according to claim 89, wherein when the selection switch is operated to deactivate the running mingled light color temperature switching process, the first controller operates to terminate the running mingled light color temperature switching process with the mingled light color temperature being thereby determined for performing the diffused light of the light-emitting unit.
 91. An LED security light comprising: a light-emitting unit; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and a time setting unit comprising a first timer and a second timer; an external control unit comprising at least a first external control device; wherein the light-emitting unit is configured with an LED load comprising a plurality of LEDs; wherein the loading and power control unit comprises a controller and a switching circuitry, wherein the switching circuitry comprises at least a semiconductor switching device; wherein the controller is electrically coupled with the switching circuitry, the light sensing control unit, the motion sensing unit, the time setting unit, and the external control unit; wherein the switching circuitry is electrically coupled with the power supply unit and the light-emitting unit, wherein the controller outputs different pulse width modulation (PWM) signals to control the switching circuitry for delivering different average electric currents to drive the light-emitting unit for generating different illuminations, wherein the controller outputs at least a first PWM signal and a second PWM signal respectively to control the switching circuitry such that the light-emitting unit respectively performs at least a first illumination mode with a first level illumination and at least a second illumination mode with a second level illumination according to signal(s) received from the light sensing control unit and the motion sensing unit; wherein at dusk when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit operates to deliver an average electric current to the LED load to turn on the light-emitting unit to perform the first illumination mode with the first level illumination for a predetermined time duration set by the first timer; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit operates to increase the average electric current delivered to the LED load of the light-emitting unit to perform the second illumination mode with the second level illumination for a preset time period set by the second timer before being switched back to the first illumination mode with the first level illumination; wherein a light intensity of the first level illumination in the first illumination mode is adjustable; wherein the first external control device outputs a first external control signal to the controller, wherein the controller correspondingly outputs a different first PWM signal to control the semiconductor switching device for adjusting the light intensity of the first level illumination in the first illumination mode; wherein a light intensity of the second level illumination is equal to or higher than the light intensity of the first level illumination; wherein at dawn when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the light-emitting unit is switched off by the loading and power control unit; wherein the first timer and the second timer are respectively designed for adjusting and setting the predetermined time duration of the first level illumination and the preset time period of the second level illumination; wherein the power supply unit is an AC/DC power converter to convert AC power into a DC power to be delivered to the switching circuitry, wherein the switching circuitry is designed with a driving circuitry to output an adequate DC voltage with a constant current electric power to drive the LED load such that an electric current passing through each LED of the LED load remains at an adequate level, and a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring LED electrical characteristics; wherein V_(th) is a reference value of a threshold voltage required to trigger each LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across each LED at which an LED construction in the plurality of LEDs could be vulnerable to a thermal damage; wherein the reference value may contain a small tolerance to accommodate a variation by different manufacturers caused by different manufacturing process; wherein the voltage V is a variable within a narrow dispersion range characterized by an LED voltage bin selected for generating a designated constant forward current; wherein when the LED load is configured with a plurality of N number LEDs or N sets of LEDs electrically connected in series, a working voltage V_(N) across the LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs or sets of LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs or sets of LEDs electrically connected in series, identically expressed as N×V_(th)<V_(N)<N×V_(max).
 92. The LED security light according to claim 91, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage V_(th) is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts subject to an operating condition that a temperature of each LED connecting pin is controlled at or below 80 degrees centigrade, wherein the voltage V across each LED of the N pieces of LEDs is required to comply with an operating constraint of 2.5 volts<V<3.5 volts and the working voltage V_(N) imposed on the LED load is thereby confined in a domain expressed by N×2.5 volts<V_(N)<N×3.5 volts.
 93. The LED security light according to claim 91, wherein when the light intensity of the second level illumination in the second illumination mode is higher than the light intensity of the first level illumination in the first illumination mode, the LED security light serves as a motion sensing security light; wherein at dusk the light-emitting unit is turned on by the light sensing control unit to perform the first level illumination with a low level light intensity, wherein when a motion intrusion is detected by the motion sensing unit, the loading and power control unit operates to increase the electric power delivered to the light-emitting unit to perform the second level illumination with a high level light intensity for the preset time period before switching back to resume the second level illumination, at dawn the light-emitting unit is turned off by the loading and power control unit, wherein the light intensity of the first level illumination is adjustable in a range between 0% and 50% of a maximum light intensity designed for the LED security light, wherein the light intensity of the second level illumination is adjustable in a range between 50% and 100% of the maximum light intensity designed for the LED security light.
 94. The LED security light according to claim 91, wherein when the light intensity of the first level illumination in the first illumination mode is adjusted to the same level of the light intensity of the second level illumination in the second illumination mode, the LED security light effectively serves as a dusk to dawn security light, wherein the light-emitting unit is turned on at dusk and turned off at dawn by the light sensing control unit.
 95. The LED security light according to claim 91, wherein the first external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by tuning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the first level illumination in a first predesigned range.
 96. The LED security light according to claim 95, wherein the first predesigned range is between 0% and 100% of a maximum light intensity designed for the LED security light.
 97. The LED security light according to claim 91, wherein the external control unit further comprises a second external control device electrically connected to the controller, wherein a light intensity of the second illumination is adjustable in a second predesigned range, wherein the second external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by turning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the second level illumination in the second predesigned range.
 98. The LED security light according to claim 97, wherein the second predesigned range is between 50% and 100% of a maximum light intensity designed for the LED security light.
 99. The LED security light according to claim 91, wherein the first timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the predetermined time duration of the first level illumination in the first illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the predetermined time duration of the first level illumination in the first illumination mode.
 100. The LED security light according to claim 99, wherein the time length of the predetermined time duration of the first level illumination is ended at a time point when the ambient light detected by the light sensing control unit is higher than the second predetermined value and the light-emitting unit accordingly is switched off by the loading and power control unit, wherein the LED security light performs a dusk to dawn security light.
 101. The LED security light according to claim 91, wherein the second timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the preset time period of the second level illumination in the second illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the preset time period of the second level illumination in the second illumination mode.
 102. The LED security light according to claim 91, wherein the first external control device is a wireless remote control device comprising a transceiver, wherein the wireless remote control device is capable of receiving an external control signal for adjusting at least an operating parameter of the LED security light, wherein when the controller receives the external control signal the controller operates to activate a process to accordingly adjust the operating parameter of the LED security light, wherein the wireless transceiver is also capable of transmitting a wireless control signal according to the received external control signal to control the same operating parameter of a neighboring LED security light.
 103. The LED security light according to claim 102, wherein the operating parameter is the light intensity of the first level illumination, the light intensity of the second level illumination, a time length of the preset time period, or a time length of the predetermined time duration.
 104. An LED security light comprising: a light-emitting unit; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; and a time setting unit comprising a first timer and a second timer; an external control unit comprising at least a first external control device; wherein the light-emitting unit is configured with an LED load comprising a plurality of LEDs; wherein the loading and power control unit comprises a controller and a switching circuitry, wherein the switching circuitry comprises at least a semiconductor switching device; wherein the controller is electrically coupled with the switching circuitry, the light sensing control unit, the motion sensing unit, the time setting unit, and the external control unit; wherein the switching circuitry is electrically coupled with the power supply unit and the light-emitting unit, wherein the controller outputs different pulse width modulation (PWM) signals to respectively control the switching circuitry for delivering different average electric currents to drive the light-emitting unit for generating different illuminations, wherein the controller outputs at least a first PWM signal and a second PWM signal respectively to control the switching circuitry such that the light-emitting unit respectively performs at least a first illumination mode with a first level illumination and at least a second illumination mode with a second level illumination according to signal(s) received from the light sensing control unit and the motion sensing unit; wherein at dusk when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit operates to deliver a first average electric current to the LED load to turn on the light-emitting unit to perform the first illumination mode with the first level illumination for a predetermined time duration set by the first timer with the motion sensing unit being deactivated; wherein upon a maturity of the predetermined time duration the loading and power control unit manages to cutoff the first average electric current delivered to the LED load to turn off the light-emitting unit and at the same time the motion sensing unit is activated; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit operates to deliver a second average electric current to the LED load of the light-emitting unit to perform the second illumination mode with the second level illumination for a preset time period set by the second timer before the light-emitting unit is switched back to a turned off state; wherein a light intensity of the first level illumination in the first illumination mode is adjustable; wherein the first external control device outputs a first external control signal to the controller, wherein the controller correspondingly outputs a different first PWM signal to control the semiconductor switching device for adjusting the light intensity of the first level illumination in the first illumination mode; wherein a light intensity of the second level illumination is equal to or higher than the light intensity of the first level illumination; wherein at dawn when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the light-emitting unit is switched off by the loading and power control unit; wherein the first timer and the second timer are respectively used for adjusting and setting the predetermined time duration of the first level illumination and the preset time period of the second level illumination; wherein the power supply unit is an AC/DC power converter to convert AC power into a DC power to be delivered to the switching circuitry, wherein the switching circuitry is designed with a driving circuitry to output an adequate DC voltage with a constant current electric power to drive the LED load such that an electric current passing through each LED of the LED load remains at an adequate level, and a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring LED electrical characteristics; wherein V_(th) is a reference value of a threshold voltage required to trigger each LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across each LED at which an LED construction in the plurality of LEDs could be vulnerable to a thermal damage; wherein the reference value may contain a small tolerance to accommodate a variation by different manufacturers caused by different manufacturing process; wherein the voltage V is a variable within a narrow dispersion range characterized by an LED voltage bin selected for generating a designated constant forward current; wherein when the LED load is configured with a plurality of N number LEDs or N sets of LEDs electrically connected in series, a working voltage V_(N) across the LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs or sets of LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs or sets of LEDs electrically connected in series, identically expressed as N×V_(th)<V_(N)<N×V_(max).
 105. The LED security light according to claim 104, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage V_(th) is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts subject to an operating condition that a temperature of each LED connecting pin is controlled at or below 80 degrees centigrade, wherein the voltage V across each LED of the N pieces of LEDs is required to comply with an operating constraint of 2.5 volts<V<3.5 volts and the working voltage V_(N) imposed on the LED load is thereby confined in a domain expressed by N×2.5 volts<V_(N)<N×3.5 volts.
 106. The LED security light according to claim 105, wherein the first external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by tuning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting a light intensity of the first level illumination in a first predesigned range.
 107. The LED security light according to claim 106, wherein the first predesigned range is between 50% and 100% of a maximum light intensity designed for the LED security light.
 108. The LED security light according to claim 104, wherein external control unit further comprises a second external control device electrically connected to the controller, wherein the second external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by turning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the second level illumination in a second predesigned range.
 109. The LED security light according to claim 108, wherein the second predesigned range is between 50% and 100% of a maximum light intensity designed for the LED security light.
 110. The LED security light according to claim 104, wherein the first timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the predetermined time duration of the first level illumination in the first illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the predetermined time duration of the first level illumination in the first illumination mode.
 111. The LED security light according to claim 110, wherein the time length of the predetermined time duration of the first level illumination is ended at a time point when the ambient light detected by the light sensing control unit is higher than the second predetermined value and the light-emitting unit accordingly is switched off by the loading and power control unit, wherein the LED security light performs a dusk to dawn security light.
 112. The LED security light according to claim 104, wherein the second timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the preset time period of the second level illumination in the second illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the preset time period of the second level illumination in the second illumination mode.
 113. An LED security light comprising: a light-emitting unit; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; a time setting unit comprising at least a first timer and at least a second timer; and an external control unit comprising at least a first external control device and at least a second external control device; wherein the light-emitting unit is configured with an LED load comprising a plurality of LEDs; wherein the loading and power control unit comprises a controller and a switching circuitry, wherein the switching circuitry comprises at least a semiconductor switching device; wherein the controller is electrically coupled with the switching circuitry, the light sensing control unit, the motion sensing unit, the time setting unit and the external control unit; wherein the switching circuitry is electrically coupled with the power supply unit and the light-emitting unit, wherein the controller outputs different pulse width modulation (PWM) signals to respectively control the switching circuitry for delivering different average electric currents to drive the LED load of the light-emitting unit for generating different illuminations, wherein the controller outputs at least a first PWM signal, at least a second PWM signal and at least a third PWM signal respectively to control the switching circuitry such that the light-emitting unit respectively performs at least a first illumination mode with a first level illumination, at least a second illumination mode with a second level illumination and at least a third illumination mode with a third level illumination; wherein at dusk when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit operates to deliver an average electric current to the LED load to turn on the light-emitting unit to perform the first illumination mode with the first level illumination for a predetermined time duration set by the first timer with the motion sensing unit being deactivated; wherein upon a maturity of the predetermined time duration the loading and power control unit manages to reduce the average electric current delivered to the LED load to enable the light-emitting unit to perform the second illumination mode with the second level illumination for a first preset time period and at the same time the motion sensing unit is activated; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit operates to increase the average electric current to the LED load of the light-emitting unit to perform the third illumination mode with the third level illumination for a second preset time period set by the second timer before the light-emitting unit is switched back to perform the second illumination with the second level illumination; wherein a light intensity of the first level illumination in the first illumination mode is adjustable; wherein the first external control device outputs a first external control signal to the controller, wherein the controller correspondingly outputs a different first PWM signal to control the semiconductor switching device for adjusting the light intensity of the first level illumination in the first illumination mode; wherein a light intensity of the second level illumination in the second illumination mode is adjustable; wherein the second external control device outputs a second external control signal to the controller, wherein the controller correspondingly outputs a different second PWM signal to control the semiconductor switching device for adjusting the light intensity of the second level illumination in the second illumination mode; wherein a light intensity of the third level illumination is higher than the light intensity of the second level illumination; wherein at dawn when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the light-emitting unit is switched off by the loading and power control unit; wherein the first timer and the second timer are respectively used for adjusting and setting the predetermined time duration of the first level illumination and the second preset time period of the third level illumination; wherein the power supply unit is an AC/DC power converter to convert AC power into a DC power to be delivered to the switching circuitry, wherein the switching circuitry is designed with a driving circuitry to output an adequate DC voltage with a constant current electric power to drive the LED load such that an electric current passing through each LED of the LED load remains at an adequate level, and a voltage V across each LED complies with an operating constraint of V_(th)<V<V_(max) featuring LED electrical characteristics; wherein V_(th) is a reference value of a threshold voltage required to trigger each LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across each LED at which an LED construction in the plurality of LEDs could be vulnerable to a thermal damage; wherein the reference value may contain a small tolerance to accommodate a variation by different manufacturers caused by different manufacturing process; wherein the voltage V is a variable within a narrow dispersion range characterized by an LED voltage bin selected for generating a designated constant forward current; wherein when the LED load is configured with a plurality of N number LEDs or N sets of LEDs electrically connected in series, a working voltage V_(N) across the LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs or sets of LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs or sets of LEDs electrically connected in series, identically expressed as N×V_(th)<V_(N)<N×V_(max).
 114. The LED security light according to claim 113, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage V_(th) is reliably estimated at 2.5 volts and the reference value of the maximum voltage is reliably estimated at 3.5 volts subject to an operating condition that a temperature of each LED connecting pin is controlled at or below 80 degrees centigrade, wherein the voltage V across each LED of the N pieces of LEDs is required to comply with an operating constraint of 2.5 volts<V<3.5 volts and the working voltage V_(N) imposed on the LED load is thereby confined in a domain expressed by N×2.5 volts<V_(N)<N×3.5 volts.
 115. The LED security light according to claim 113, wherein the first external. control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by turning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the first level illumination in a first predesigned range.
 116. The LED security light according to claim 115, wherein the first predesigned. Range is between 50% and 100% of a maximum light intensity designed for the LED security light.
 117. The LED security light according to claim 113, wherein the second external control device comprises a voltage divider, wherein when the voltage divider is. operated a DC voltage is selected and generated by turning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the second level illumination in a second predesigned range.
 118. The LED security light according to claim 113, wherein the external control unit further comprises a third external control device electrically connected to the controller, wherein the light intensity of the third level illumination is adjustable, wherein the third external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by turning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the third level illumination in a third predesigned range.
 119. The LED security light according to claim 118, wherein the third predesigned range is between 50% and 100% of a maximum light intensity designed for the LED security light.
 120. The LED security light according to claim 113, wherein the first timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the predetermined time duration of the first level illumination in the first illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the predetermined time duration of the first level illumination in the first illumination mode.
 121. The LED security light according to claim 120, wherein the time length of the predetermined time duration of the first level illumination is ended at a time point when the ambient light detected by the light sensing control unit is higher than the second predetermined value and the light-emitting unit accordingly is switched off at dawn by the loading and power control unit, wherein the LED security light performs a dusk to dawn security light.
 122. The LED security light according to claim 113, wherein the second timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the second preset time period of the third level illumination in the third illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the second preset time period of the third level illumination in the third illumination mode.
 123. The LED security light according to claim 113, wherein the time setting unit further comprises a third timer electrically connected with the controller, wherein a time length of the first preset time period is adjustable, wherein the third timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the first preset time period of the second level illumination in the second illumination mode, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the first preset time period of the second level illumination in the second illumination mode.
 124. An LED security light comprising: a light-emitting unit; a loading and power control unit; a light sensing control unit; a motion sensing unit; a power supply unit; a time setting unit comprising at least a first timer; and an external control unit comprising at least a first external control device; wherein the light-emitting unit is configured with an LED load comprising a plurality of LEDs; wherein the loading and power control unit comprises a controller and a switching circuitry, wherein the switching circuitry comprises at least a semiconductor switching device; wherein the controller is electrically coupled with the switching circuitry, the light sensing control unit, the motion sensing unit, the first timer and the first external control device; wherein the switching circuitry is electrically coupled with the power supply unit and the light-emitting unit, wherein the controller outputs at least one pulse width modulation (PWM) signal to control the switching circuitry for delivering at least one average electric current to drive the LED load of the light-emitting unit for generating an illumination according to signal(s) received from the light sensing control unit and the motion sensing unit; wherein at dusk when an ambient light detected by the light sensing control unit is lower than a first predetermined value, the loading and power control unit operates to activate the motion sensing unit to be ready for detecting a motion intrusion; wherein when a motion signal is detected by the motion sensing unit, the loading and power control unit operates to deliver an average electric current to the LED load of the light-emitting unit to perform a high level illumination for a preset time period set by the first timer before being switched back to a turned off state for detecting a next motion intrusion; wherein a light intensity of the high level illumination is adjustable in a range between 50% (included) and 100% (included) of a maximum light intensity designed for the LED security light; wherein the first external control device outputs a first external control signal to the controller, wherein the controller correspondingly outputs a first PWM signal to control the semiconductor switching device for adjusting the light intensity of the high level illumination; wherein at dawn when the ambient light detected by the light sensing control unit is higher than a second predetermined value, the light-emitting unit is switched off by the loading and power control unit; wherein the power supply unit is an AC/DC power converter to convert AC power into a DC power to be delivered to the switching circuitry, wherein the switching circuitry is designed with a driving circuitry to output an adequate DC voltage with a constant current electric power to drive the LED load such that an electric current passing through each LED of the LED load remains at an adequate level, and a voltage V across each LED is required to comply with an operating constraint of V_(th)<V<V_(max) featuring LED electrical characteristics; wherein V_(th) is a reference value of a threshold voltage required to trigger each LED to start emitting light and V_(max) is a reference value of a maximum operating voltage across each LED at which at least an LED construction in the plurality of LEDs could be vulnerable to a thermal damage; wherein the reference value may contain a small tolerance to accommodate a variation by different manufacturers caused by different manufacturing process; wherein the voltage V is a variable within a narrow dispersion range characterized by an LED voltage bin selected for generating a designated constant forward current; wherein when the LED load is configured with a plurality of N number LEDs or. N sets of LEDs electrically connected in series, a working voltage V_(N) across the LED load is confined in a domain between a minimum voltage equal to the sum of the threshold voltages of all LEDs or sets of LEDs electrically connected in series and a maximum voltage equal to the sum of the maximum operating voltages of all LEDs or sets of LEDs electrically connected in series, identically expressed as N×V_(th)<V_(N)<N×V_(max).
 125. The LED security light according to claim 124, wherein when the plurality of LEDs are phosphor based white light LEDs produced by coating at least one phosphor compound on surfaces of blue light LEDs, the reference value of the threshold voltage V_(th) is reliably estimated at 2.5 volts with a narrow tolerance and the reference value of the maximum voltage is reliably estimated at 3.5 volts with a narrow tolerance subject to an operating condition that a temperature of each LED connecting pin is controlled at or below 80 degrees centigrade, wherein the voltage V across each LED of the N pieces of LEDs is required to comply with an operating constraint of 2.5 volts<V<3.5 volts and the working voltage V_(N) imposed on the LED load is thereby confined in a domain expressed by N×2.5 volts<V_(N)<N×3.5 volts.
 126. The LED security light according to claim 124, wherein the first external control device comprises a voltage divider, wherein when the voltage divider is operated, a DC voltage is selected and generated by tuning a variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the light intensity of the high level illumination in a predesigned range.
 127. The LED security light according to claim 126, wherein the predesigned range is between 50% and 100% of a maximum light intensity designed for the LED.
 128. The LED security light according to claim 124, wherein the first timer of the time setting unit is configured with a voltage divider for adjusting and setting a time length of the preset time period of the high level illumination, wherein the voltage divider comprises a variable resistor, wherein the voltage divider is electrically coupled to the controller, wherein when the voltage divider is operated, a DC voltage value is selected and generated by tuning the variable resistor to trigger the controller to activate a corresponding process designed for adjusting and setting the time length of the preset time period of the high level illumination.
 129. The LED security light according to claim 124, wherein the first external control device is a wireless remote control device comprising a transceiver, wherein the wireless remote control device is capable of receiving an external control signal for adjusting at least an operating parameter of the LED security light, wherein when the controller receives the external control signal, the controller operates to activate a process to accordingly adjust the operating parameter of the LED security light, wherein the wireless receiver is also capable of transmitting a wireless control signal according to the received external control signal to control the same operating parameter of a neighboring LED security light.
 130. The LED security light according to claim 129, wherein the operating parameter is the light intensity of the high level illumination or a time length of the preset time period. 